Purpose of This PDQ Summary
Overview
General Information
History
Laboratory/Animal/Preclinical Studies
Human/Clinical Studies
Adverse Effects
Overall Level of Evidence for Aromatherapy and Essential Oils
Changes to This Summary (05/29/2008)
More Information

Purpose of This PDQ Summary

This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the use of aromatherapy and essential oils as a treatment for cancer. The summary is reviewed regularly and updated as necessary by the PDQ Cancer Complementary and Alternative Medicine Editorial Board ¹.

Information about the following is included in this summary:

• A brief history of aromatherapy and essential oils research.
• The results of clinical studies of aromatherapy and essential oils.
• Possible side effects of aromatherapy and essential oils.

This summary is intended as a resource to inform and assist clinicians and other health professionals who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.

Some of the reference citations in the summary are accompanied by a level of evidence designation. These designations are intended to help the readers assess the strength of the evidence supporting the use of specific interventions or treatment strategies. The PDQ Cancer Complementary and Alternative Medicine Editorial Board uses a formal evidence ranking system ² in developing its level of evidence designations. These designations should not be used as a basis for reimbursement determinations.

This summary is also available in a patient version ³, which is written in less technical language.

Overview

This complementary and alternative medicine (CAM) information summary provides an overview of the use of aromatherapy and essential oils primarily to improve the quality of life of cancer patients. This summary includes a brief history of aromatherapy, a review of laboratory studies and clinical trials, and possible adverse effects associated with aromatherapy use.

This summary contains the following key information:

• Aromatherapy is the therapeutic use of essential oils (also known as volatile oils) from plants (flowers, herbs, or trees) for the improvement of physical, emotional, and spiritual well-being.



• Aromatherapy is used by patients with cancer primarily as a supportive care agent for general well-being.



• Aromatherapy is used with other complementary treatments (e.g., massage and acupuncture) as well as standard treatment.



• Essential oils are volatile liquid substances extracted from aromatic plant material by steam distillation or mechanical expression; oils produced with the aid of chemical solvents are not considered true essential oils.



• Essential oils are available in the United States for inhalation and topical treatment. Topical treatments are generally used in diluted forms.



• Aromatherapy is not widely administered via ingestion.



• The effects of aromatherapy are theorized to result from the effect of odorant molecules from essential oils on the brain’s emotional center, the limbic system. Topical application of aromatic oils may exert antibacterial, anti-inflammatory, and analgesic effects.



• Studies in animals show sedative and stimulant effects of specific essential oils as well as positive effects on behavior and the immune system. Functional imaging studies in humans support the influence of odors on the limbic system and its emotional pathways.



• Human clinical trials have investigated aromatherapy primarily in the treatment of stress and anxiety in patients with critical illnesses or in other hospitalized patients. Several clinical trials involving patients with cancer have been published.



• Aromatherapy has a relatively low toxicity profile when administered by inhalation or diluted topical application.



• Aromatherapy products do not need approval by the U.S. Food and Drug Administration because there is no claim for treatment of specific diseases.



• Repeated exposure to lavender and tea tree oils by topical administration has been associated with reversible prepubertal gynecomastia.

Many of the medical and scientific terms used in the summary are hypertext linked (at first use in each section) to the NCI Dictionary ⁴, which is oriented toward nonexperts. When a linked term is clicked, a definition will appear in a separate window. All linked terms and their corresponding definitions will appear as a glossary in the printable version of the summary.

Reference citations in some PDQ CAM information summaries may include links to external Web sites that are operated by individuals or organizations for the purpose of marketing or advocating the use of specific treatments or products. These reference citations are included for informational purposes only. Their inclusion should not be viewed as an endorsement of the content of the Web sites, or of any treatment or product, by the PDQ Cancer CAM Editorial Board or the National Cancer Institute.

General Information

Aromatherapy is a derivative of herbal medicine, which is itself a subset of the biological or nature-based complementary and alternative medicine (CAM) therapies. Aromatherapy has been defined as the therapeutic use of essential oils from plants for the improvement of physical, emotional, and spiritual well-being. The proponents of aromatherapy claim it is an all-natural, nontoxic adjunct to conventional medicines.

Essential oils are volatile liquid substances extracted from aromatic plant material by steam distillation or mechanical expression. Oils produced with the aid of chemical solvents are not considered true essential oils, as the solvent residues can alter the purity of the oils themselves and lead to adulteration of the fragrance or to skin irritation.

Essential oils are made up of a large array of chemical components that consist of the secondary metabolites found in various plant materials. The major chemical components of essential oils include terpenes, esters, aldehydes, ketones, alcohols, phenols, and oxides, which are volatile and may produce characteristic odors. Different types of oils contain varying amounts of each of these compounds, which are said to give each oil its particular fragrance and therapeutic characteristics. Different varieties of the same species may have different chemotypes (different chemical composition of the same plant species as a result of different harvesting methods or locations) and thus different types of effects.[1]

Synthetic odors are often made up of many of the same compounds, which are synthesized and combined with other novel odor-producing chemicals. Most aromatherapists believe that synthetic fragrances are inferior to essential oils because they lack natural or vital energy; however, this has been contested by odor psychologists and biochemists.[2]

Aromatherapy is used or claimed to be useful for a vast array of symptoms and conditions. A book on aromatherapy for children suggests aromatherapy remedies for everything from acne to whooping cough.[3] Published studies regarding the uses of aromatherapy have generally focused on its psychological effects (used as a stress reliever or anxiolytic agent) or its use as a topical treatment for skin-related conditions.

A large body of literature has been published on the effects of odors on the human brain and emotions. Some studies have tested the effects of essential oils on mood, alertness, and mental stress in healthy subjects. Other studies investigated the effects of various (usually synthetic) odors on task performance, reaction time, and autonomic parameters or evaluated the direct effects of odors on the brain via electroencephalogram patterns and functional imaging studies.[4] Such studies have consistently shown that odors can produce specific effects on human neuropsychological and autonomic function and that odors can influence mood, perceived health, and arousal. These studies suggest that odors may have therapeutic applications in the context of stressful and adverse psychological conditions.

Practitioners of aromatherapy apply essential oils using several different methods, including direct inhalation via diffuser or drops of oil placed near the patient (e.g., on a pillow); aromatherapy massage, which is the application to the body of essential oils diluted in a carrier oil; and other direct and indirect applications such as placing drops of oil in bathwater, lotions, or dressings. Different aromatherapy practitioners may have different recipes for treating specific illnesses, involving various combinations of oils and methods of application. Differences seem to be practitioner-dependent, with some common uses more accepted throughout the aromatherapy community. Training in aromatherapy is available at several schools throughout the United States and United Kingdom; but there is no professional standardization, and no license is required to practice in either country. Thus, there is not a great deal of consistency in the specific treatments for specific illnesses among practitioners. This lack of standardization has led to poor consistency in research on the effects of aromatherapy: because anecdotal evidence alone or previous experience drives the choice of oils, different researchers often choose different oils when studying the same applications.

Although essential oils are given internally by aromatherapists in France and Germany, their use is generally limited to inhalation or topical application in the United Kingdom and United States. Nonmedical use of essential oils is common in the flavoring and fragrance industries, however, and most essential oils have been classified as GRAS (generally recognized as safe), at specified concentration limits, by the U.S. Food and Drug Administration (FDA).

Aromatherapy products do not need approval by the FDA.

References

1. Wildwood C: The Encyclopedia of Aromatherapy. Rochester, Vt: Healing Arts Press, 1996. 
   
   
2. Dodd GH: The molecular dimension in perfumery. In: Van Toller S, Dodd GH, eds.: Perfumery: The Psychology and Biology of Fragrance. New York, NY: Chapman and Hall, 1988, pp 19-46. 
   
   
3. Worwood VA: Aromatherapy for the Healthy Child: More Than 300 Natural, Non-Toxic, and Fragrant Essential Oil Blends. Novato, Calif: New World Library, 2000. 
   
   
4. Buchbauer G, Jirovetz L, Jäger W, et al.: Fragrance compounds and essential oils with sedative effects upon inhalation. J Pharm Sci 82 (6): 660-4, 1993.  [PUBMED Abstract]
   
   

History

Proponents of aromatherapy report that aromatic or essential oils have been used for thousands of years as stimulants or sedatives of the nervous system and as treatments for a wide range of other disorders. [1] They link it historically to the use of infused oils and unguents in the Bible and ancient Egypt,[1] remedies used throughout the Middle Ages and the Renaissance,[2] and the burning of aromatic plants in various primitive religious rites. The current applications of aromatherapy did not come about until the early 20th century when the French chemist and perfumer Rene Gattefosse coined the term “aromatherapy” and published a book of that name in 1937.[2] Gattefosse proposed the use of aromatherapy to treat diseases in virtually every organ system, citing mostly anecdotal and case-based evidence.[2]

Although Gattefosse and his colleagues in France, Italy, and Germany studied the effects of aromatherapy for some 30 years, its use went out of fashion midcentury and was rediscovered by another Frenchman, a physician, Jean Valnet, in the latter part of the century. Valnet published his book The Practice of Aromatherapy in 1982,[3] at which time the practice became more well-known in Britain and the United States. Through the 1980s and 1990s, as patients in Western countries became increasingly interested in complementary and alternative medicine (CAM) treatments, aromatherapy developed a following that continues to this day. In addition to the growing use of essential oils by nurses and aromatherapy practitioners for specific medical issues, the popularity of aromatherapy has also been exploited by cosmetics companies that have created lines of essential oil-based (though often with a synthetic component) cosmetics and toiletries, claiming to improve mood and well-being in their users.

Despite the growing popularity of aromatherapy in the latter part of the 20th century (especially in the United Kingdom), little research on aromatherapy was available in the English-language medical literature until the early or mid-1990s. The research that began to appear in the 1990s was most often conducted by nurses, who tended to be the primary practitioners of aromatherapy in the United States and United Kingdom (although it is dispensed by medical doctors in France and Germany). Aromatherapists now publish their own journal, the International Journal of Essential Oil Therapeutics. Also, many studies regarding the effects of odor on the brain and other systems in animals and healthy humans have been published in the context of odor psychology and neurobiology (and in the absence of the specific term aromatherapy).

In addition to topical antibacterial uses,[4] aromatherapy has also been proposed for use in wound care [5] and to treat a variety of localized symptoms and illnesses such as alopecia, eczema, and pruritus. [6-10] Aromatherapy has also been studied via inhalation for airway reactivity.[11]

Studies on aromatherapy have examined a variety of other conditions: sedation and arousal;[12,13] startle reflex and reaction time;[14,15] psychological states such as mood, anxiety, and general sense of well-being;[16-31] neurologic impairment;[24] chronic renal failure;[25] agitation in patients with dementia;[32-36] smoking withdrawal symptoms;[37,38] postoperative nausea; [39] nausea and emesis in combination with fatigue, pain, and anxiety in patients in labor;[26,27,40] pain alone;[41-43] and pain in combination with other symptoms.[23,24,26,27]

Published articles have described the use of aromatherapy in specific hospital settings such as cancer wards, hospices, and other areas where patients are critically ill and require palliative care for pain, nausea, generalized stress, and anxiety.[44] These observational studies provide examples of the clinical uses of aromatherapy (and other CAM modalities), though they are generally not evidence-based. Subjects have included hospitalized children with HIV, [45] homebound patients with terminal disease,[46] and hospitalized patients with leukemia. [47] Studies of aromatherapy use with mental health patients have also been conducted.[48,49] Most of the resulting articles describe successful incorporation of aromatherapy into the treatment of these patients, though outcomes are clearly subjective.

Theories about the mechanism of action of aromatherapy and essential oils differ, depending on the community studying them. Proponents of aromatherapy often cite the connection between olfaction and the limbic system in the brain as the basis for the effects of aromatherapy on mood and emotions; less is said about proposed mechanisms for its effects on other parts of the body. Most of the aromatherapy literature, however, lacks in-depth neurophysiological studies on the nature of olfaction and its link to the limbic system, and it generally does not cite research that shows these links. Proponents of aromatherapy also believe that the effects of the treatments are based on the special nature of the essential oils used. Some authors propose that the extraction of essential oils from whole aromatic plants causes them to contain a life force or vitality that allegedly sets essential oils apart from other (synthetic) fragrances.[50] This argument suggests that essential oils produce effects on the body that are greater than the sum of the individual chemical components of the scents.

These assertions have been contested by the biochemistry and psychology communities, which take a different view of the possible mechanism of action of odors on the human brain (most do not differentiate the odors produced by essential oils from those of synthetic fragrances).[50] This neurobiological view, which focuses mostly on the emotional and psychological effects of fragrances (as opposed to the other symptomatic effects claimed by aromatherapists), takes into account what is known about olfactory transduction and the connection of the olfactory system to other central nervous system functions; however, it is primarily theoretical because of the lack of significant research addressing this topic.

References

1. Tisserand R: Essential oils as psychotherapeutic agents. In: Van Toller S, Dodd GH, eds.: Perfumery: The Psychology and Biology of Fragrance. New York, NY: Chapman and Hall, 1988, pp 167-80. 
   
   
2. Gattefosse RM: Gattefosse's Aromatherapy. Essex, England:CW Daniel, 1993. 
   
   
3. Valnet J: The Practice of Aromatherapy: A Classic Compendium of Plant Medicines & Their Healing Properties. Rochester, NY: Healing Arts Press, 1990. 
   
   
4. Dryden MS, Dailly S, Crouch M: A randomized, controlled trial of tea tree topical preparations versus a standard topical regimen for the clearance of MRSA colonization. J Hosp Infect 56 (4): 283-6, 2004.  [PUBMED Abstract]
   
   
5. Hartman D, Coetzee JC: Two US practitioners' experience of using essential oils for wound care. J Wound Care 11 (8): 317-20, 2002.  [PUBMED Abstract]
   
   
6. Baker J: Essential oils: a complementary therapy in wound management. J Wound Care 7 (7): 355-7, 1998.  [PUBMED Abstract]
   
   
7. Asquith S: The use of aromatherapy in wound care. J Wound Care 8 (6): 318-20, 1999.  [PUBMED Abstract]
   
   
8. Hay IC, Jamieson M, Ormerod AD: Randomized trial of aromatherapy. Successful treatment for alopecia areata. Arch Dermatol 134 (11): 1349-52, 1998.  [PUBMED Abstract]
   
   
9. Anderson C, Lis-Balchin M, Kirk-Smith M: Evaluation of massage with essential oils on childhood atopic eczema. Phytother Res 14 (6): 452-6, 2000.  [PUBMED Abstract]
   
   
10. Ro YJ, Ha HC, Kim CG, et al.: The effects of aromatherapy on pruritus in patients undergoing hemodialysis. Dermatol Nurs 14 (4): 231-4, 237-8, 256; quiz 239, 2002.  [PUBMED Abstract]
    
    
11. Cohen BM, Dressler WE: Acute aromatics inhalation modifies the airways. Effects of the common cold. Respiration 43 (4): 285-93, 1982.  [PUBMED Abstract]
    
    
12. Diego MA, Jones NA, Field T, et al.: Aromatherapy positively affects mood, EEG patterns of alertness and math computations. Int J Neurosci 96 (3-4): 217-24, 1998.  [PUBMED Abstract]
    
    
13. Motomura N, Sakurai A, Yotsuya Y: Reduction of mental stress with lavender odorant. Percept Mot Skills 93 (3): 713-8, 2001.  [PUBMED Abstract]
    
    
14. Miltner W, Matjak M, Braun C, et al.: Emotional qualities of odors and their influence on the startle reflex in humans. Psychophysiology 31 (1): 107-10, 1994.  [PUBMED Abstract]
    
    
15. Millot JL, Brand G, Morand N: Effects of ambient odors on reaction time in humans. Neurosci Lett 322 (2): 79-82, 2002.  [PUBMED Abstract]
    
    
16. Stevenson C: Measuring the effects of aromatherapy. Nurs Times 88 (41): 62-3, 1992 Oct 7-13.  [PUBMED Abstract]
    
    
17. Dunn C, Sleep J, Collett D: Sensing an improvement: an experimental study to evaluate the use of aromatherapy, massage and periods of rest in an intensive care unit. J Adv Nurs 21 (1): 34-40, 1995.  [PUBMED Abstract]
    
    
18. Buckle J: Aromatherapy. Nurs Times 89 (20): 32-5, 1993 May 19-25.  [PUBMED Abstract]
    
    
19. Hadfield N: The role of aromatherapy massage in reducing anxiety in patients with malignant brain tumours. Int J Palliat Nurs 7 (6): 279-85, 2001.  [PUBMED Abstract]
    
    
20. Wilkinson S: Aromatherapy and massage in palliative care. Int J Palliat Nurs 1 (1): 21-30, 1995. 
    
    
21. Wilkinson S, Aldridge J, Salmon I, et al.: An evaluation of aromatherapy massage in palliative care. Palliat Med 13 (5): 409-17, 1999.  [PUBMED Abstract]
    
    
22. Corner J, Cawler N, Hildebrand S: An evaluation of the use of massage and essential oils on the wellbeing of cancer patients. Int J Palliat Nurs 1 (2): 67-73, 1995. 
    
    
23. Louis M, Kowalski SD: Use of aromatherapy with hospice patients to decrease pain, anxiety, and depression and to promote an increased sense of well-being. Am J Hosp Palliat Care 19 (6): 381-6, 2002 Nov-Dec.  [PUBMED Abstract]
    
    
24. Walsh E, Wilson C: Complementary therapies in long-stay neurology in-patient settings. Nurs Stand 13 (32): 32-5, 1999 Apr 28-May 4.  [PUBMED Abstract]
    
    
25. Itai T, Amayasu H, Kuribayashi M, et al.: Psychological effects of aromatherapy on chronic hemodialysis patients. Psychiatry Clin Neurosci 54 (4): 393-7, 2000.  [PUBMED Abstract]
    
    
26. Burns E, Blamey C: Complementary medicine. Using aromatherapy in childbirth. Nurs Times 90 (9): 54-60, 1994 Mar 2-8.  [PUBMED Abstract]
    
    
27. Burns EE, Blamey C, Ersser SJ, et al.: An investigation into the use of aromatherapy in intrapartum midwifery practice. J Altern Complement Med 6 (2): 141-7, 2000.  [PUBMED Abstract]
    
    
28. Kite SM, Maher EJ, Anderson K, et al.: Development of an aromatherapy service at a Cancer Centre. Palliat Med 12 (3): 171-80, 1998.  [PUBMED Abstract]
    
    
29. Komori T, Fujiwara R, Tanida M, et al.: Effects of citrus fragrance on immune function and depressive states. Neuroimmunomodulation 2 (3): 174-80, 1995 May-Jun.  [PUBMED Abstract]
    
    
30. Wiebe E: A randomized trial of aromatherapy to reduce anxiety before abortion. Eff Clin Pract 3 (4): 166-9, 2000 Jul-Aug.  [PUBMED Abstract]
    
    
31. Lehrner J, Eckersberger C, Walla P, et al.: Ambient odor of orange in a dental office reduces anxiety and improves mood in female patients. Physiol Behav 71 (1-2): 83-6, 2000 Oct 1-15.  [PUBMED Abstract]
    
    
32. Ballard CG, O'Brien JT, Reichelt K, et al.: Aromatherapy as a safe and effective treatment for the management of agitation in severe dementia: the results of a double-blind, placebo-controlled trial with Melissa. J Clin Psychiatry 63 (7): 553-8, 2002.  [PUBMED Abstract]
    
    
33. Smallwood J, Brown R, Coulter F, et al.: Aromatherapy and behaviour disturbances in dementia: a randomized controlled trial. Int J Geriatr Psychiatry 16 (10): 1010-3, 2001.  [PUBMED Abstract]
    
    
34. Holmes C, Hopkins V, Hensford C, et al.: Lavender oil as a treatment for agitated behaviour in severe dementia: a placebo controlled study. Int J Geriatr Psychiatry 17 (4): 305-8, 2002.  [PUBMED Abstract]
    
    
35. Gray SG, Clair AA: Influence of aromatherapy on medication administration to residential-care residents with dementia and behavioral challenges. Am J Alzheimers Dis Other Demen 17 (3): 169-74, 2002 May-Jun.  [PUBMED Abstract]
    
    
36. Cohen-Mansfield J, Werner P: The effects of an enhanced environment on nursing home residents who pace. Gerontologist 38 (2): 199-208, 1998.  [PUBMED Abstract]
    
    
37. Rose JE, Behm FM: Inhalation of vapor from black pepper extract reduces smoking withdrawal symptoms. Drug Alcohol Depend 34 (3): 225-9, 1994.  [PUBMED Abstract]
    
    
38. Sayette MA, Parrott DJ: Effects of olfactory stimuli on urge reduction in smokers. Exp Clin Psychopharmacol 7 (2): 151-9, 1999.  [PUBMED Abstract]
    
    
39. Tate S: Peppermint oil: a treatment for postoperative nausea. J Adv Nurs 26 (3): 543-9, 1997.  [PUBMED Abstract]
    
    
40. Oyama H, Kaneda M, Katsumata N, et al.: Using the bedside wellness system during chemotherapy decreases fatigue and emesis in cancer patients. J Med Syst 24 (3): 173-82, 2000.  [PUBMED Abstract]
    
    
41. Dale A, Cornwell S: The role of lavender oil in relieving perineal discomfort following childbirth: a blind randomized clinical trial. J Adv Nurs 19 (1): 89-96, 1994.  [PUBMED Abstract]
    
    
42. Göbel H, Schmidt G, Soyka D: Effect of peppermint and eucalyptus oil preparations on neurophysiological and experimental algesimetric headache parameters. Cephalalgia 14 (3): 228-34; discussion 182, 1994.  [PUBMED Abstract]
    
    
43. Marchand S, Arsenault P: Odors modulate pain perception: a gender-specific effect. Physiol Behav 76 (2): 251-6, 2002.  [PUBMED Abstract]
    
    
44. Buckle J: Clinical Aromatherapy: Essential Oils in Practice. 2nd ed. New York, NY: Churchill Livingston, 2003. 
    
    
45. Styles JL: The use of aromatherapy in hospitalized children with HIV disease. Complement Ther Nurs Midwifery 3 (1): 16-20, 1997.  [PUBMED Abstract]
    
    
46. Rimmer L: The clinical use of aromatherapy in the reduction of stress. Home Healthc Nurse 16 (2): 123-6, 1998.  [PUBMED Abstract]
    
    
47. Stringer J: Massage and aromatherapy on a leukaemia unit. Complement Ther Nurs Midwifery 6 (2): 72-6, 2000.  [PUBMED Abstract]
    
    
48. Hicks G: Aromatherapy as an adjunct to care in a mental health day hospital. J Psychiatr Ment Health Nurs 5 (4): 317, 1998.  [PUBMED Abstract]
    
    
49. Mantle F: The role of alternative medicine in treating postnatal depression. Complement Ther Nurs Midwifery 8 (4): 197-203, 2002.  [PUBMED Abstract]
    
    
50. Dodd GH: The molecular dimension in perfumery. In: Van Toller S, Dodd GH, eds.: Perfumery: The Psychology and Biology of Fragrance. New York, NY: Chapman and Hall, 1988, pp 19-46. 
    
    

Laboratory/Animal/Preclinical Studies

Numerous studies on the topical antibacterial effects of essential oils have been published; most have found the oils to have significant antimicrobial activity.[1]

Studies on rats in Europe and Japan have shown that exposure to various odors can result in stimulation or sedation, as well as changes in behavioral responses to stress and pain. A study [2] on the sedative effects of essential oils and other fragrance compounds (mostly individual chemical components of the oils) on rat motility showed that lavender oil (Lavandula angustifolia Miller [synonyms: Lavandula spicata L.; Lavandula vera DC.]) in particular had a significant sedative effect, and several single-oil constituents (as opposed to whole essential oils) had similarly strong effects. The authors do not comment on the presumed mechanism for this effect, though they suggest that the difference in results between the different oils (some of which were found to be stimulating, some sedative) is related to the “different chemical structures of the compounds…and functional groups…indicating the essential role of the volatility of the fragrance compounds and its bioavailability.” The differences in bioavailability are ascribed to different levels of lipophilia, with the more lipophilic oils producing the most sedative effects. The researchers also found significant plasma levels of the fragrance compounds after inhalation, suggesting that the effects of aromatherapy result from a direct pharmacological interaction rather than an indirect central nervous system relay.

Other studies have investigated the effects of aromatherapy on rats’ behavioral and immunological responses to painful, stressful, or startling stimuli. In two European studies, rats exposed to pleasant odors during painful stimuli exhibited decreased pain-related behaviors, with some variation in response between the sexes.[3,4] Two studies from Japan showed an improvement in immunological and behavioral markers in rats exposed to fragrances while under stressful conditions.[5,6]

References

1. Aridoğan BC, Baydar H, Kaya S, et al.: Antimicrobial activity and chemical composition of some essential oils. Arch Pharm Res 25 (6): 860-4, 2002.  [PUBMED Abstract]
   
   
2. Buchbauer G, Jirovetz L, Jäger W, et al.: Fragrance compounds and essential oils with sedative effects upon inhalation. J Pharm Sci 82 (6): 660-4, 1993.  [PUBMED Abstract]
   
   
3. Aloisi AM, Ceccarelli I, Masi F, et al.: Effects of the essential oil from citrus lemon in male and female rats exposed to a persistent painful stimulation. Behav Brain Res 136 (1): 127-35, 2002.  [PUBMED Abstract]
   
   
4. Jahangeer AC, Mellier D, Caston J: Influence of olfactory stimulation on nociceptive behavior in mice. Physiol Behav 62 (2): 359-66, 1997.  [PUBMED Abstract]
   
   
5. Shibata H, Fujiwara R, Iwamoto M, et al.: Immunological and behavioral effects of fragrance in mice. Int J Neurosci 57 (1-2): 151-9, 1991.  [PUBMED Abstract]
   
   
6. Fujiwara R, Komori T, Noda Y, et al.: Effects of a long-term inhalation of fragrances on the stress-induced immunosuppression in mice. Neuroimmunomodulation 5 (6): 318-22, 1998 Nov-Dec.  [PUBMED Abstract]
   
   

Human/Clinical Studies

No studies in the published peer-reviewed literature discuss aromatherapy as a treatment for cancer. The studies discussed below, most of which were conducted in patients with cancer, primarily focus on other health-related conditions and on quality of life measures such as stress and anxiety levels.

Among the fewest articles published on the subject are clinical trials involving aromatherapy. A major review published in 2000 [1] focused on six studies investigating treatment or prevention of anxiety with aromatherapy massage. Although the studies suggested that aromatherapy massage had a mild transient anxiolytic effect, the authors concluded that the research done at that time was not sufficiently rigorous or consistent to prove the effectiveness of aromatherapy in treating anxiety. This review excluded trials related to other effects of aromatherapy (such as pain control) and did not include any studies looking at the effects of odors that were not specifically labeled as aromatherapy.

A review undertaken in 2004 investigated whether aromatherapy and/or massage decreased psychological morbidity, lessened symptom distress, or improved quality of life in cancer patients.[2] The review reported that the most consistently found effect of massage or aromatherapy massage was on anxiety, with four of the trials (a total of 207 patients) reporting a reduction in anxiety. The authors state that contradictory evidence exists on whether any additional benefit on anxiety is conferred by the addition of aromatherapy. Of three trials that examined depression in cancer patients, only one reported significant differences. Two trials reported a reduction in nausea and three reported a reduction in pain. The authors concluded that on the basis of limited evidence, massage and aromatherapy confer short-term benefits on psychological well-being; however, evidence is mixed on whether aromatherapy itself enhances the effect of massage.

Several of the studies included in the Cochrane Database of Systematic Reviews are discussed in more detail. A randomized controlled pilot study examined the effects of adjunctive aromatherapy massage on mood, quality of life, and physical symptoms in patients with cancer.[3] Forty-six patients were randomly assigned to conventional day care alone or day care plus weekly aromatherapy massage using a standardized blend of oils for 4 weeks. Patients self-rated their mood, quality of life, and the intensity of the two symptoms that were the most concerning to them at the beginning of the study and at weekly intervals thereafter. Of the 46 patients, only 11 of 23 (48%) in the aromatherapy group and 18 of 23 (78%) in the control group completed all 4 weeks. Patient-reported mood, symptoms, and quality of life improved in both groups, and there was no statistically significant difference between the two groups in any of these measures.

Another randomized controlled trial examined the effects of aromatherapy massage and massage alone on 42 patients with advanced cancer over a 4-week period.[4] Patients were randomly assigned to receive weekly massages with or without aromatherapy; the treatment group (aromatherapy group) received massages with lavender essential oil (Lavandula angustifolia Miller [synonyms: Lavandula spicata L.; Lavandula vera DC.]) and an inert carrier oil, and the control group (massage group) received either an inert carrier oil alone or no intervention. The authors reported no significant long-term benefits of aromatherapy or massage in pain control, quality of life, or anxiety, but sleep scores (as measured by the Verran and Snyder-Halpern sleep scale) improved significantly in both groups. The authors also reported statistically significant reductions in depression scores (as measured by the Hospital Anxiety and Depression Scale [HADS]) in the massage-only group.

A placebo-controlled, double-blind, randomized trial conducted in Australia investigated the effects of inhalation aromatherapy on anxiety during radiation therapy.[5] A total of 313 patients receiving radiation therapy were randomly assigned to one of three groups: carrier oil with fractionated oils, carrier oil only, or pure essential oils of lavender, bergamot (Citrus aurantium L. ssp. bergamia [Risso] Wright & Arn. [Rutaceae]; [synonym: Citrus bergamia Risso]), and cedarwood (Cedrus atlantica [Endl.] Manetti ex Carriere [Pinaceae]). All three groups received the oils by inhalation during their radiation therapy. The authors reported no significant differences in depression (as measured by HADS) or psychological effects (as measured by the Somatic and Psychological Health Report) between the groups. The group that received only the carrier oil showed a statistically significant decrease in anxiety (as measured by HADS) compared with the other two groups.

Another randomized controlled trial investigated the effects of massage or aromatherapy massage in 103 cancer patients who were randomly assigned to receive massage using a carrier oil (massage group) or massage using a carrier oil plus the Roman chamomile essential oil (Chamaemelum nobile [L.] All. [synonym: Anthemis nobilis L.]) (aromatherapy massage group).[6] Two weeks after the massage, the authors found a statistically significant reduction in anxiety in the aromatherapy massage group (as measured by the State-Trait Anxiety Inventory) and an improvement in symptoms (as measured by the Rotterdam Symptom Checklist [RSCL]; the subscales with improved scores were psychological, quality of life, severe physical, and severe psychological). The authors reported that the massage-only group showed improvement on four RSCL subscales; however, these improvements did not reach statistical significance.

A study whose primary objective was evaluating an aromatherapy service following changes made after an initial pilot at a U.K. cancer center also reported on the experiences of patients referred to the service.[7] Of 89 patients originally referred, 58 completed six aromatherapy sessions. The authors reported significant improvements in anxiety and depression (as measured by HADS) at the completion of the six sessions, as compared with before the six sessions. A small study examined the physical and psychological effects of aromatherapy massage in eight patients with primary malignant brain tumors attending their first follow-up appointment after radiation therapy.[8] The author reported no psychological benefit in these patients from aromatherapy massage (as measured by HADS) but reported a statistically significant reduction in blood pressure, pulse, and respiratory rate.

Antibiotic -resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin -resistant enterococcus, are an increasing problem worldwide, causing intractable wound infections. Compounded phytochemicals, such as lemongrass, eucalyptus, melaleuca, clove, thyme with butylated hydroxyl toluene, triclosan (0.3%), and 95 undematured ethanol (69.7%) are being investigated against MRSA in vitro . No clinical trials have been performed.[9]

Two topical MRSA eradication regimens were compared in hospital patients. A standard treatment, which included mupirocin 2% nasal ointment, chlorhexidine gluconate 4% soap, and silver sulfadiazine 1% cream was given versus a tea tree oil regimen, which included tea tree 10% cream and tea tree 5% body wash. Both were administered for 5 days. One hundred fourteen patients received the standard treatment, and 56 (49%) were cleared of MRSA carriage. One hundred ten patients received the tea tree oil regimen, and 46 (41%) were cleared of MRSA carriage. There was no significant difference between treatment regimens (Fisher's exact test; P = .0286). In a small group of patients, the tea tree oil regimen was associated with a higher clearance rate of MRSA carriage in the axilla, groin, and wound sites, but the difference versus standard treatment was not significant.[10]

References

1. Cooke B, Ernst E: Aromatherapy: a systematic review. Br J Gen Pract 50 (455): 493-6, 2000.  [PUBMED Abstract]
   
   
2. Fellowes D, Barnes K, Wilkinson S: Aromatherapy and massage for symptom relief in patients with cancer. Cochrane Database Syst Rev (2): CD002287, 2004.  [PUBMED Abstract]
   
   
3. Wilcock A, Manderson C, Weller R, et al.: Does aromatherapy massage benefit patients with cancer attending a specialist palliative care day centre? Palliat Med 18 (4): 287-90, 2004.  [PUBMED Abstract]
   
   
4. Soden K, Vincent K, Craske S, et al.: A randomized controlled trial of aromatherapy massage in a hospice setting. Palliat Med 18 (2): 87-92, 2004.  [PUBMED Abstract]
   
   
5. Graham PH, Browne L, Cox H, et al.: Inhalation aromatherapy during radiotherapy: results of a placebo-controlled double-blind randomized trial. J Clin Oncol 21 (12): 2372-6, 2003.  [PUBMED Abstract]
   
   
6. Wilkinson S, Aldridge J, Salmon I, et al.: An evaluation of aromatherapy massage in palliative care. Palliat Med 13 (5): 409-17, 1999.  [PUBMED Abstract]
   
   
7. Kite SM, Maher EJ, Anderson K, et al.: Development of an aromatherapy service at a Cancer Centre. Palliat Med 12 (3): 171-80, 1998.  [PUBMED Abstract]
   
   
8. Hadfield N: The role of aromatherapy massage in reducing anxiety in patients with malignant brain tumours. Int J Palliat Nurs 7 (6): 279-85, 2001.  [PUBMED Abstract]
   
   
9. Sherry E, Boeck H, Warnke PH: Percutaneous treatment of chronic MRSA osteomyelitis with a novel plant-derived antiseptic. BMC Surg 1: 1, 2001.  [PUBMED Abstract]
   
   
10. Dryden MS, Dailly S, Crouch M: A randomized, controlled trial of tea tree topical preparations versus a standard topical regimen for the clearance of MRSA colonization. J Hosp Infect 56 (4): 283-6, 2004.  [PUBMED Abstract]
    
    

Adverse Effects

Safety testing on essential oils has shown minimal adverse effects. Several oils have been approved for use as food additives and are classified as generally recognized as safe (GRAS) by the U.S. Food and Drug Administration; however, ingestion of large amounts of essential oils is not recommended. In addition, a few cases of contact dermatitis have been reported, mostly in aromatherapists who have had prolonged skin contact with oils in the context of aromatherapy massage.[1] Some essential oils (e.g., camphor oil) can cause local irritation; therefore, care should be taken when applying them. Phototoxicity has occurred when essential oils (particularly citrus oils) are applied directly to the skin before sun exposure. One case report also showed airborne contact dermatitis in the context of inhaled aromatherapy without massage.[2] Most often, aromatherapy uses undefined mixtures of essential oils without specifying the plant sources. Allergic reactions are sometimes reported, especially following topical administration. As essential oils age, they are often oxidized so the chemical composition changes. Individual psychological associations with odors may result in adverse effects. Repeated exposure to lavender and tea tree oils by topical administration has been associated with reversible prepubertal gynecomastia. Lavender and tea tree oils have estrogenic and antiandrogenic activities, and there is a theoretical concern for women at high risk for hormonally sensitive breast cancer when using lavender and tea tree oils.[3]

References

1. Bilsland D, Strong A: Allergic contact dermatitis from the essential oil of French marigold (Tagetes patula) in an aromatherapist. Contact Dermatitis 23 (1): 55-6, 1990.  [PUBMED Abstract]
   
   
2. Schaller M, Korting HC: Allergic airborne contact dermatitis from essential oils used in aromatherapy. Clin Exp Dermatol 20 (2): 143-5, 1995.  [PUBMED Abstract]
   
   
3. Henley DV, Lipson N, Korach KS, et al.: Prepubertal gynecomastia linked to lavender and tea tree oils. N Engl J Med 356 (5): 479-85, 2007.  [PUBMED Abstract]
   
   

Overall Level of Evidence for Aromatherapy and Essential Oils

To assist readers in evaluating the results of human studies of complementary and alternative medicine (CAM) treatments for cancer, the strength of the evidence (i.e., the levels of evidence) associated with each type of treatment is provided whenever possible. To qualify for a levels of evidence analysis, a study must:

• Be published in a peer-reviewed scientific journal.
• Report on a therapeutic outcome or outcomes, such as tumor response, improvement in survival, or measured improvement in quality of life.
• Describe clinical findings in enough detail that a meaningful evaluation can be made.

Separate levels of evidence scores are assigned to qualifying human studies on the basis of statistical strength of the study design and scientific strength of the treatment outcomes (i.e., endpoints) measured. The resulting two scores are then combined to produce an overall score. A table showing the levels of evidence scores for qualifying human studies cited in this summary is presented below. For an explanation of the scores and additional information about levels of evidence analysis of CAM treatments for cancer, refer to Levels of Evidence for Human Studies of Cancer Complementary and Alternative Medicine ².

References

1. Wilcock A, Manderson C, Weller R, et al.: Does aromatherapy massage benefit patients with cancer attending a specialist palliative care day centre? Palliat Med 18 (4): 287-90, 2004.  [PUBMED Abstract]
   
   
2. Soden K, Vincent K, Craske S, et al.: A randomized controlled trial of aromatherapy massage in a hospice setting. Palliat Med 18 (2): 87-92, 2004.  [PUBMED Abstract]
   
   
3. Graham PH, Browne L, Cox H, et al.: Inhalation aromatherapy during radiotherapy: results of a placebo-controlled double-blind randomized trial. J Clin Oncol 21 (12): 2372-6, 2003.  [PUBMED Abstract]
   
   
4. Gravett P: Aromatherapy treatment for patients with Hickman line infection following high-dose chemotherapy. International Journal of Aromatherapy 11 (1): 18-9, 2001. 
   
   
5. Gravett P: Treatment of gastrointestinal upset following high-dose chemotherapy. International Journal of Aromatherapy 11 (2): 84-6, 2001. 
   
   
6. Hadfield N: The role of aromatherapy massage in reducing anxiety in patients with malignant brain tumours. Int J Palliat Nurs 7 (6): 279-85, 2001.  [PUBMED Abstract]
   
   
7. Wilkinson S, Aldridge J, Salmon I, et al.: An evaluation of aromatherapy massage in palliative care. Palliat Med 13 (5): 409-17, 1999.  [PUBMED Abstract]
   
   
8. Wilkinson S: Aromatherapy and massage in palliative care. Int J Palliat Nurs 1 (1): 21-30, 1995. 
   
   
9. Corner J, Cawler N, Hildebrand S: An evaluation of the use of massage and essential oils on the wellbeing of cancer patients. Int J Palliat Nurs 1 (2): 67-73, 1995. 
   
   
10. Evans B: An audit into the effects of aromatherapy massage and the cancer patient in palliative and terminal care. Complement Ther Med 3 (4): 239-41, 1995. 
    
    

Changes to This Summary (05/29/2008)

The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.

Human/Clinical Studies ⁶

Added text ⁷ to state that antibiotic-resistant bacteria, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococcus, are an increasing problem worldwide, causing intractable wound infections (cited Sherry et al. as reference 9).

Added text ⁸ to state that of the two topical MRSA eradication regimens that were compared in hospital patients, both were administered for 5 days, the tea tree oil regimen showed a slightly higher clearance rate than the standard treatment, but the difference was not significant.

Adverse Effects ⁹

Added text ¹⁰ to state that there is a theoretical concern for women at high risk for hormonally sensitive breast cancer when using lavender and tea tree oils (cited Henley et al. as reference 3).

More Information

Additional Information about CAM Therapies

• The National Center for Complementary and Alternative Medicine ¹¹ (NCCAM).
• The National Cancer Institute Office of Cancer Complementary and Alternative Medicine ¹² (OCCAM).
• CAM on PubMed ¹³, a special subset of the PubMed scientific literature database created through a partnership between NCCAM and the National Library of Medicine.

About PDQ

• PDQ® - NCI's Comprehensive Cancer Database ¹⁴

  Full description of the NCI PDQ database.

Other PDQ Summaries

• PDQ® Cancer Information Summaries: Adult Treatment ¹⁵

  Treatment options for adult cancers.

• PDQ® Cancer Information Summaries: Pediatric Treatment ¹⁶

  Treatment options for childhood cancers.

• PDQ® Cancer Information Summaries: Supportive and Palliative Care ¹⁷

  Side effects of cancer treatment, management of cancer-related complications and pain, and psychosocial concerns.

• PDQ® Cancer Information Summaries: Screening/Detection (Testing for Cancer) ¹⁸

  Tests or procedures that detect specific types of cancer.

• PDQ® Cancer Information Summaries: Prevention ¹⁹

  Risk factors and methods to increase chances of preventing specific types of cancer.

• PDQ® Cancer Information Summaries: Genetics ²⁰

  Genetics of specific cancers and inherited cancer syndromes, and ethical, legal, and social concerns.

• PDQ® Cancer Information Summaries: Complementary and Alternative Medicine ²¹

  Information about complementary and alternative forms of treatment for patients with cancer.

Important:

This information is intended mainly for use by doctors and other health care professionals. If you have questions about this topic, you can ask your doctor, or call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).

Glossary Terms

A disorder of the skin in which oil glands and hair glands become inflamed.

The technique of inserting thin needles through the skin at specific points on the body to control pain and other symptoms. It is a type of complementary and alternative medicine.

Another treatment used together with the primary treatment. Its purpose is to assist the primary treatment. Also called adjunct therapy.

An unwanted side effect of treatment.

A condition in which a person is unable to relax and be still. The person may be very tense and irritable, and become easily annoyed by small things. He or she may be eager to have an argument, and be unwilling to work with caregivers to make the situation better.

A chemical substance found in beer, wine, and liquor. Alcohol is also found in some medicines, mouthwashes, essential oils (scented liquid taken from plants), and household products.

A type of chemical substance made from alcohol. Aldehydes are found in essential oils (scented liquid taken from plants).

A hypersensitive immune reaction to a substance that normally is harmless or would not cause an immune response in most people. An allergic response may cause harmful symptoms such as itching or inflammation or tissue injury.

The lack or loss of hair from areas of the body where hair is usually found. Alopecia can be a side effect of some cancer treatments.

A drug that reduces pain. Analgesics include aspirin, acetaminophen, and ibuprofen.

A process in which anything complex is separated into simple or less complex parts.

An incomplete description of the medical and treatment history of one or more patients. Anecdotal reports may be published in places other than peer-reviewed, scientific journals.

Having to do with reducing inflammation.

A substance that kills bacteria or stops them from growing and causing disease.

A drug used to treat infections caused by bacteria and other microorganisms.

A substance that kills microorganisms such as bacteria or mold, or stops them from growing and causing disease.

Feelings of fear, dread, and uneasiness that may occur as a reaction to stress. A person with anxiety may sweat, feel restless and tense, and have a rapid heart beat. Extreme anxiety that happens often over time may be a sign of an anxiety disorder.

A drug used in the treatment of anxiety and muscle spasms.

A type of complementary and alternative medicine that uses plant oils that give off strong pleasant aromas (smells) to promote relaxation, a sense of well-being, and healing.

A type of complementary and alternative medicine that uses rubbing and kneading of the skin with plant oils that give off strong, pleasant aromas (smells) to promote relaxation, a sense of well-being, and healing.

Having an odor, which often is pleasant or spicy.

The state of being alert and ready to respond, or waking from sleep.

The underarm or armpit.

A large group of single-cell microorganisms. Some cause infections and disease in animals and humans. The singular of bacteria is bacterium.

A type of orange tree grown in Italy. The essential oil from the peel of this orange is used in perfume, to get rid of insects, and to flavor tea. Bergamot oil is also used in aromatherapy for depression, anxiety, and poor digestion. The scientific name for the bergamot orange tree is Citrus bergamia.

The ability of a drug or other substance to be absorbed and used by the body. Orally bioavailable means that a drug or other substance that is taken by mouth can be absorbed and used by the body.

A scientist who has special training in the study of the chemicals and processes that occur in all living things.

Pertaining to biology or to life and living things. In medicine, refers to a substance made from a living organism or its products. Biologicals may be used to prevent, diagnose, treat or relieve of symptoms of a disease. For example, antibodies, interleukins, and vaccines are biologicals. Biological also refers to parents and children who are related by blood.

The force of circulating blood on the walls of the arteries. Blood pressure is taken using two measurements: systolic (measured when the heart beats, when blood pressure is at its highest) and diastolic (measured between heart beats, when blood pressure is at its lowest). Blood pressure is written with the systolic blood pressure first, followed by the diastolic blood pressure (for example 120/80).

A procedure to replace bone marrow that has been destroyed by treatment with high doses of anticancer drugs or radiation. Transplantation may be autologous (an individual's own marrow saved before treatment), allogeneic (marrow donated by someone else), or syngeneic (marrow donated by an identical twin).

The growth of abnormal cells in the tissues of the brain. Brain tumors can be benign (non-cancerous) or malignant (cancerous).

Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.

A substance that comes from the wood and bark of the camphor tree or is made in the laboratory. It has a very unique smell and taste and is used in commercial products (for example, mothballs). Camphor is used in topical anti-infective and anti-pruritic (anti-itching) agents.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

An oil with little or no scent that is used to dilute or “carry” essential oils (scented liquid taken from plants).

A detailed report of the diagnosis, treatment, and follow-up of an individual patient. Case reports also contain some demographic information about the patient (for example, age, gender, ethnic origin).

A type of evergreen tree with hard fragrant wood that is a member of the cypress family. The oil from the wood is used in soaps, shampoos, bath salts, perfumes, aromatherapy, and to keep insects away. The scientific name is Juniperus virginiana. Also called Eastern red cedar and red cedar.

The brain and spinal cord. Also called CNS.

A family of plants with daisy-like flowers. Two types are German chamomile and Roman or English chamomile. These are used in teas to calm and relax, to improve sleep, and to help with stomach problems. The essential oil (scented liquid taken from plants) of chamomile is used in perfumes, shampoos, lotions, and aromatherapy.

A disease or condition that persists or progresses over a long period of time.

Having to do with the examination and treatment of patients.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical trial.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.

Forms of treatment that are used in addition to (complementary) or instead of (alternative) standard treatments. These practices generally are not considered standard medical approaches. Standard treatments go through a long and careful research process to prove they are safe and effective, but less is known about most types of CAM. CAM may include dietary supplements, megadose vitamins, herbal preparations, special teas, acupuncture, massage therapy, magnet therapy, spiritual healing, and meditation. Also called CAM.

Practices often used to enhance or complement standard treatments. They generally are not recognized by the medical community as standard or conventional medical approaches. Complementary medicine may include dietary supplements, megadose vitamins, herbal preparations, special teas, acupuncture, massage therapy, magnet therapy, spiritual healing, and meditation.

In science, a substance that is made up of more than one ingredient.

A clinical study that includes all eligible patients identified by the researchers during the study registration period. The patients are treated in the order in which they are identified. This type of study usually does not have a control group.

In a clinical trial, the group that does not receive the new treatment being studied. This group is compared to the group that receives the new treatment, to see if the new treatment works.

A clinical study that includes a comparison (control) group. The comparison group receives a placebo, another treatment, or no treatment at all.

A system in which medical doctors and other healthcare professionals (such as nurses, pharmacists, and therapists) treat symptoms and diseases using drugs, radiation, or surgery. Also called allopathic medicine, biomedicine, mainstream medicine, orthodox medicine, and Western medicine.

A condition in which a person loses the ability to think, remember, learn, make decisions, and solve problems. Symptoms may also include personality changes and emotional problems. There are many causes of dementia, including Alzheimer disease, brain cancer, and brain injury. Dementia usually gets worse over time.

A mental condition marked by ongoing feelings of sadness, despair, loss of energy, and difficulty dealing with normal daily life. Other symptoms of depression include feelings of worthlessness and hopelessness, loss of pleasure in activities, changes in eating or sleeping habits, and thoughts of death or suicide. Depression can affect anyone, and can be successfully treated. Depression affects 15-25% of cancer patients.

In chemistry, a compound produced from or related to another.

Inflammation of the skin.

To make something thinner, weaker, less concentrated, or less pure by adding something to it.

In medicine, a disturbance of normal functioning of the mind or body. Disorders may be caused by genetic factors, disease, or trauma.

A clinical trial in which neither the medical staff nor the person knows which of several possible therapies the person is receiving.

A group of conditions in which the skin becomes inflamed, forms blisters, and becomes crusty, thick, and scaly. Eczema causes burning and itching, and may occur over a long period of time. Atopic dermatitis is the most common type of eczema.

A recording of electrical activity in the brain. It is made by placing electrodes on the scalp (the skin covering the top of the head), and impulses are sent to a special machine. An EEG may be used to diagnose brain and sleep disorders. Also called EEG.

Vomiting.

In clinical trials, an event or outcome that can be measured objectively to determine whether the intervention being studied is beneficial. The endpoints of a clinical trial are usually included in the study objectives. Some examples of endpoints are survival, improvements in quality of life, relief of symptoms, and disappearance of the tumor.

The scented liquid taken from certain plants using steam or pressure. Essential oils contain the natural chemicals that give the plant its “essence” (specific odor and flavor). Essential oils are used in perfumes, food flavorings, medicine, and aromatherapy.

A type of chemical substance that is a combination of acid and alcohol. Esters are found in essential oils (scented liquid taken from plants).

A type of evergreen tree that is a member of the myrtle family. Oil from the leaves is used in very small amounts in mouthwash and in medicines and candy used to treat and soothe sore throats and coughs. It has also been used in some cultures to treat many other medical problems. The scientific name is Eucalyptus globulus.

In medicine, a preparation of a substance obtained from plants, animals, or bacteria and used as a drug or in drugs.

A condition marked by extreme tiredness and inability to function due lack of energy. Fatigue may be acute or chronic.

Monitoring a person's health over time after treatment. This includes keeping track of the health of people who participate in a clinical study or clinical trial for a period of time, both during the study and after the study ends.

An agency in the U.S. federal government whose mission is to protect public health by making sure that food, cosmetics, and nutritional supplements are safe to use and truthfully labeled. The Food and Drug Administration also makes sure that drugs, medical devices, and equipment are safe and effective, and that blood for transfusions and transplant tissue are safe. Also called FDA.

A pleasant, sweet odor.

A noninvasive tool used to observe functioning in the brain or other organs by detecting changes in chemical composition, blood flow, or both.

Refers to the stomach and intestines. Also called GI.

A type of plant that is native to southern Africa and has white, pink, purple, or red flowers and 3- to 5-lobed leaves. An essential oil that smells like roses is taken from the leaves and used in perfume, in mosquito repellants, and in aromatherapy to treat skin problems and to reduce stress. The scientific name is Pelargonium graveolens. Also called pelargonium.

A plant whose daisy-like flowers are used in tea to calm and relax, improve sleep, and help stomach problems. German chamomile has been studied in the prevention of mucositis (mouth sores) caused by chemotherapy and radiation therapy. It has also been used in some cultures to treat skin conditions, mild infections, and other disorders. The scientific name is Matricaria recutita.

The area where the thigh meets the abdomen.

A type of medicine that uses roots, stems, leaves, flowers, or seeds of plants to improve health, prevent disease, and treat illness.

The cause of acquired immunodeficiency syndrome (AIDS). Also called human immunodeficiency virus.

A program that provides special care for people who are near the end of life and for their families, either at home, in freestanding facilities, or within hospitals.

The activity of the immune system against foreign substances (antigens).

In the laboratory (outside the body). The opposite of in vivo (in the body).

The number of new cases of a disease diagnosed each year.

Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.

A method of putting fluids, including drugs, into the bloodstream. Also called intravenous infusion.

Taking into the body by mouth.

In medicine, refers to the act of taking a substance into the body by breathing.

A type of chemical substance used in perfumes, paints, solvents, and found in essential oils (scented liquid taken from plants). Ketones are also made by the body when there is not enough insulin.

Research done in a laboratory. These studies may use test tubes or animals to find out if a drug, procedure, or treatment is likely to be useful. Laboratory studies take place before any testing is done in humans.

A plant with aromatic leaves and flowers that is a member of the mint family. Oil from the flowers has been used in some cultures to treat certain medical problems, to keep insects away, and to wash in. It is also used in aromatherapy. Perillyl alcohol, a substance found in lavender, is being studied in cancer prevention and treatment. The scientific name is Lavandula angustifolia. Also called English lavender and true lavender.

Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of blood cells to be produced and enter the bloodstream.

A ranking system used to describe the strength of the results measured in a clinical trial or research study. The design of the study (such as a case report for an individual patient or a randomized double-blinded controlled clinical trial) and the endpoints measured (such as survival or quality of life) affect the strength of the evidence.

A network of structures in the brain involved in memory and emotions.

Able to dissolve, be dissolved in, or absorb lipids (fats).

Restricted to the site of origin, without evidence of spread.

Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

A treatment in which the soft tissues of the body are kneaded, rubbed, tapped, and stroked. Massage therapy may help people relax, relieve stress and pain, lower blood pressure, and improve circulation. It is being studied in the treatment of cancer symptoms such as lack of energy, pain, swelling, and depression.

A person’s overall psychological and emotional condition. Good mental health is a state of well-being in which a person is able to cope with everyday events, think clearly, be responsible, meet challenges, and have good relationships with others.

A substance made or used when the body breaks down food, drugs or chemicals, or its own tissue (for example, fat or muscle tissue). This process, called metabolism, makes energy and the materials needed for growth, reproduction, and maintaining health. It also helps get rid of toxic substances.

A method of treatment. For example, surgery and chemotherapy are treatment modalities.

The smallest particle of a substance that has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms. If they contain more than one atom, the atoms can be the same (an oxygen molecule has two oxygen atoms) or different (a water molecule has two hydrogen atoms and one oxygen atom). Biological molecules, such as proteins and DNA, can be made up of many thousands of atoms.

A disease or the incidence of disease within a population. Morbidity also refers to adverse effects caused by a treatment.

By or having to do with the nose.

The National Cancer Institute, part of the National Institutes of Health of the United States Department of Health and Human Services, is the Federal Government's principal agency for cancer research. The National Cancer Institute conducts, coordinates, and funds cancer research, training, health information dissemination, and other programs with respect to the cause, diagnosis, prevention, and treatment of cancer. Access the National Cancer Institute Web site at http://www.cancer.gov. Also called NCI.

A feeling of sickness or discomfort in the stomach that may come with an urge to vomit. Nausea is a side effect of some types of cancer therapy.

The organized network of nerve tissue in the body. It includes the central nervous system (the brain and spinal cord), the peripheral nervous system (nerves that extend from the spinal cord to the rest of the body), and other nerve tissue.

Having to do with nerves or the nervous system.

Describes a clinical trial or other experiment in which the researchers know what treatments are being given to each study subject or experimental group. If human subjects are involved, they know what treatments they are receiving.

Not harmful or destructive.

A health professional trained to care for people who are ill or disabled.

A type of study in which individuals are observed or certain outcomes are measured. No attempt is made to affect the outcome (for example, no treatment is given).

A smell.

A substance that gives off a smell.

A substance used on the skin to soothe or heal wounds, burns, rashes, scrapes, or other skin problems. Also called unguent.

The sense of smell.

The parts of the body involved in sensing smell, including the nose and many parts of the brain. Smell may affect emotion, behavior, memory, and thought.

A series of events in which cells in the nose bind to scent-bearing molecules and send electrical signals to the brain where they are perceived as smells.

A part of the body that performs a specific function. For example, the heart is an organ.

A specific result or effect that can be measured. Examples of outcomes include decreased pain, reduced tumor size, and improvement of disease.

A type of chemical substance that is a combination of oxygen and another substance. Oxides are found in essential oils.

Care given to improve the quality of life of patients who have a serious or life-threatening disease. The goal of palliative care is to prevent or treat as early as possible the symptoms of a disease, side effects caused by treatment of a disease, and psychological, social, and spiritual problems related to a disease or its treatment. Also called comfort care, supportive care, and symptom management.

A bushy herb that is a member of the mint family. A strong-smelling oil taken from the leaves is used in perfumes, incense, detergents, and hair conditioners. It has been used in some cultures to prevent disease. The scientific name is Pogostemon cablin

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

A very poisonous chemical substance made from tar and also found in some plants and essential oils (scented liquid taken from plants). Phenol is used to make plastics, nylon, epoxy, medicines, and to kill germs. Also called carbolic acid.

A condition in which the skin or eyes become very sensitive to sunlight or other forms of light. It can be caused by taking certain drugs, or rubbing certain essential oils (scented liquid taken from plants) or other topical agents into the skin. Phototoxicity causes sunburn, blisters, and other skin problems.

A substance found in plants. Some phytochemicals may reduce the risk of cancer.

A chemical substance that comes from plants and is used to make vitamins E and K. Phytol is also found in soaps, beauty care products, and household products.

The initial study examining a new method or treatment.

Refers to a clinical study in which the control patients receive a placebo.

The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.

After surgery.

In medicine, action taken to decrease the chance of getting a disease or condition. For example, cancer prevention includes avoiding risk factors (such as smoking, obesity, lack of exercise, and radiation exposure) and increasing protective factors (such as getting regular physical activity, staying at a healthy weight, and having a healthy diet).

The original tumor.

Itching. Severe itching may be a side effect of some cancer treatments and a symptom of some types of cancers.

Having to do with how the mind works and how thoughts and feelings affect behavior.

A specialist who can talk with patients and their families about emotional and personal matters, and can help them make decisions.

The overall enjoyment of life. Many clinical trials assess the effects of cancer and its treatment on the quality of life. These studies measure aspects of an individual’s sense of well-being and ability to carry out various activities.

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.

A study in which the participants are assigned by chance to separate groups that compare different treatments; neither the researchers nor the participants can choose which group. Using chance to assign people to groups means that the groups will be similar and that the treatments they receive can be compared objectively. At the time of the trial, it is not known which treatment is best. It is the patient's choice to be in a randomized trial.

A treatment plan that specifies the dosage, the schedule, and the duration of treatment.

A condition in which the kidneys stop working and are not able to remove waste and extra water from the blood or keep body chemicals in balance. Acute or severe renal failure happens suddenly (for example, after an injury) and may be treated and cured. Chronic renal failure develops over many years, may be caused by conditions like high blood pressure or diabetes, and cannot be cured. Chronic renal failure may lead to total and long-lasting renal failure, called end-stage renal disease (ESRD). A person in ESRD needs dialysis (the process of cleaning the blood by passing it through a membrane or filter) or a kidney transplant. Also called kidney failure.

In medicine, an improvement related to treatment.

A type of chamomile plant with daisy-like white flowers that is found in Europe, North America, and Argentina. The dried flowers are used in teas to calm and relax, to improve sleep, and to help with stomach problems. Its essential oil (scented liquid taken from plants) is used in perfumes, shampoos, face creams, lotions, and aromatherapy. The scientific names are Chamaemelum nobile and Anthemis nobilis. Also called English chamomile.

A drug or substance used to calm a person down, relieve anxiety, or help a person sleep.

A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

In statistics, describes a mathematical measure of difference between groups. The difference is said to be significant if it is greater than what might be expected to happen by chance alone. Also called statistically significant.

A liquid that is able to dissolve a solid.

Having to do with deep, often religious, feelings and beliefs, including a person’s sense of peace, purpose, connection to others, and beliefs about the meaning of life.

In medicine, treatment that experts agree is appropriate, accepted, and widely used. Health care providers are obligated to provide patients with standard therapy. Also called best practice and standard of care.

Describes a mathematical measure of difference between groups. The difference is said to be statistically significant if it is greater than what might be expected to happen by chance alone. Also called significant.

In medicine, a family of drugs used to treat depression, attention-deficit disorder (a common disorder in which children are inattentive, impulsive, and/or over-active), and narcolepsy (a sleep disorder that causes uncontrollable sleepiness). Stimulants increase brain activity, alertness, attention, and energy. They also raise blood pressure and increase heart rate and breathing rate.

Care given to improve the quality of life of patients who have a serious or life-threatening disease. The goal of supportive care is to prevent or treat as early as possible the symptoms of a disease, side effects caused by treatment of a disease, and psychological, social, and spiritual problems related to a disease or its treatment. Also called comfort care, palliative care, and symptom management.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

Having to do with symptoms, which are signs of a condition or disease.

Having to do with substances that are man-made instead of taken from nature.

A tree that is a member of the myrtle family. Oil from the tea tree is used in shampoos and skin care products and to treat skin infections. It has been used in some cultures to treat other skin conditions, including acne, burns, and insect bites. The scientific name is Melaleuca alternifolia.

Disease that cannot be cured and will cause death.

A type of strong-smelling chemical substance found in some plants, especially trees that have cones. Terpenes are found in essential oils (scented liquid taken from plants).

Having to do with treating disease and helping healing take place.

Treatment.

On the surface of the body.

The extent to which something is poisonous or harmful.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancerous), or malignant (cancerous). Also called neoplasm.

An East Indian plant that is a member of the ginger family and is used as a spice and food color. The underground stems are used in some cultures to treat certain stomach problems. The substance in turmeric that gives it a yellow color (curcumin) is being studied in the treatment of cancer, Alzheimer disease, cystic fibrosis, and psoriasis. The scientific name is Curcuma longa. Also called Indian saffron and jiang huang.

A substance used on the skin to soothe or heal wounds, burns, rashes, scrapes, or other skin problems. Also called ointment.

A plant whose roots are used as a sedative and to treat certain medical conditions. It is being studied as a way to improve sleep in cancer patients undergoing treatment. Also called garden heliotrope, garden valerian, Indian valerian, Mexican valerian, Pacific valerian, Valeriana officinalis, and Valerianae radix.

An antibiotic drug used to fight resistant bacterial infections.

Necessary to maintain life. Breathing is a vital function.

A serious bacterial infection of the lungs and breathing tubes that spreads easily. Whooping cough begins like a cold, but develops into severe coughing and gasping for air. Long spells of coughing may cause vomiting, and broken blood vessels in the eyes and on the skin. Also called pertussis.

A break in the skin or other body tissues caused by injury or surgical incision (cut).