Aloe (Aloe vera)
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| Aloe |
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- Transparent gel from the pulp of the meaty leaves of Aloe vera has been used topically for thousands of years to treat wounds, skin infections, burns, and numerous other dermatologic conditions. Dried latex from the inner lining of the leaf has traditionally been used as an oral laxative.
- There is strong scientific evidence in support of the laxative properties of aloe latex, based on the well-established cathartic properties of anthroquinone glycosides (found in aloe latex). However, aloe's therapeutic value compared with other approaches to constipation remains unclear.
- There is promising preliminary support from laboratory, animal, and human studies that topical aloe gel has immunomodulatory properties that may improve wound healing and skin inflammation.
- Acemannan, Aloe africana , Aloe arborescens Miller, Aloe barbadensis , Aloe barbadesis , Aloe capensis , aloe-coated gloves, Aloe ferox , aloe latex, aloe mucilage, Aloe perfoliata , Aloe perryi Baker, Aloe saponaria , Aloe spicata , Aloe vulgari , Barbados aloe, bitter aloe, burn plant, Cape aloe, Carrisyn, Curaçao aloe, elephant's gall, first-aid plant, Ghai kunwar, Ghikumar, hirukattali, Hsiang-Dan, jelly leek, kumari, lahoi, laloi, lily of the desert, Lu-Hui, medicine plant, Mediterranean aloe, miracle plant, mocha aloes, musabbar, natal aloes, nohwa, plant of immortality, plant of life, rokai, sabilla, Savila, Socotrine aloe, subr, true aloe, Venezuela aloe, Za'bila, Zanzibar aloe.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
| Uses based on scientific evidence | Grade* |
| Constipation (laxative)
Dried latex from the inner lining of aloe leaves has been used traditionally as a laxative taken by mouth. Although few studies have been conducted to assess this effect of aloe in humans, the laxative properties of aloe components such as aloin are well supported by scientific evidence. A combination herbal remedy containing aloe was found to be an effective laxative, although it is not clear if this effect was due to aloe or to other ingredients in the product. Further study is needed to establish dosing and to compare the effectiveness and safety of aloe with other commonly used laxatives.
| B |
| Genital herpes
Limited evidence from human studies suggests that extract from Aloe vera in a hydrophilic cream may be an effective treatment of genital herpes in men (better than aloe gel or placebo). Additional research is needed in this area before a strong recommendation can be made.
| B |
| Psoriasis vulgaris
Early evidence suggests that an extract from aloe in a hydrophilic cream may be an effective treatment of psoriasis vulgaris. Additional research is needed in this area before a strong recommendation can be made.
| B |
| Seborrheic dermatitis (seborrhea, dandruff)
Early study of aloe lotion suggests effectiveness for treating seborrheic dermatitis when applied to the skin. Further study is needed in this area before a strong recommendation can be made.
| B |
| Cancer prevention
There is early evidence that oral aloe may reduce the risk of developing lung cancer. Further study is needed in this area to clarify if it is aloe itself or other factors that may cause this benefit.
| C |
| Canker sores (aphthous stomatitis)
There is weak evidence that treatment of recurrent aphthous ulcers of the mouth with aloe gel may reduce pain and increase the amount of time between the appearance of new ulcers. Further study is needed before a firm recommendation can be made.
| C |
| Diabetes (type 2)
Study results are mixed. More research is needed to explore the effectiveness and safety of aloe in diabetics.
| C |
| Dry skin
Traditionally, aloe has been used as a moisturizer. Early low-quality studies suggest aloe may effectively reduce skin dryness. Higher quality studies are needed in this area.
| C |
| HIV infection
Without further human trials, the evidence cannot be considered convincing either in favor or against this use of aloe.
| C |
| Lichen planus
Limited study suggests that aloe may be a helpful, safe treatment for lichen planus, which is a chronic inflammatory disease that affects the lining of the mouth. Additional study is needed.
| C |
| Skin burns
Early evidence suggests that aloe may aid healing of mild to moderate skin burns. Further study is needed in this area.
| C |
| Skin ulcers
Early studies suggest aloe may help heal skin ulcers. High-quality studies comparing aloe alone with placebo are needed.
| C |
| Ulcerative colitis (including inflammatory bowel disease)
There is limited but promising research of the use of oral aloe vera in ulcerative colitis (UC), compared to placebo. It is not clear how aloe vera compares to other treatments used for UC.
| C |
| Wound healing
Study results of aloe on wound healing are mixed with some studies reporting positive results and others showing no benefit or potential worsening of the condition. Further study is needed, since wound healing is a popular use of topical aloe.
| C |
| Mucositis
There is early evidence that oral aloe vera does not prevent or improve mucositis (mouth sores) associated with radiation therapy.
| D |
| Pressure ulcers
Early well-designed studies in humans found no benefit of topical acemannan hydrogel (a component of aloe gel) in the treatment of pressure ulcers.
| D |
| Radiation dermatitis
Reports in the 1930s of topical aloe's beneficial effects on skin after radiation exposure lead to widespread use in skin products. Currently, aloe gel is sometimes recommended for skin irritation caused by prolonged exposure to radiation, although scientific evidence suggests a lack of benefit in this area.
| D |
*Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use;
F: Strong scientific evidence against this use.
Grading rationale
Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Alzheimer's disease, antifungal, antimicrobial, antioxidant, antitumor, antiviral, arthritis (osteoarthritis, rheumatoid arthritis), asthma, bacterial skin infections, birth control, blood vessel disorders, bowel disorders, chronic fatigue syndrome, congestive heart failure, frostbite, gingivitis, hair loss, heart disease prevention, hepatitis, high cholesterol, human papilloma virus (HPV), itchiness (skin), kidney or bladder stones, leukemia, lichen planus (a skin condition), parasitic worm infections, Parkinson's disease, periodontal surgical rinse, scratches or superficial wounds of the eye, stomach acid reduction, sunburn, systemic lupus erythematosus (SLE), tic douloureux (trigeminal neuralgia, severe facial pain), untreatable tumors, vaginal contraceptive, yeast infections of the skin.
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (18 years and older)
- Pure Aloe vera gel is often used liberally on the skin three to four times per day for the treatment of sunburn and other minor burns. Creams and lotions are also available. There are no reports that using aloe on the skin causes absorption of chemicals into the body that may cause significant side effects. Skin products are available that contain aloe alone or aloe combined with other active ingredients.
- The dose often recommended for constipation is the minimum amount to maintain a soft stool, typically 0.04-0.17 gram of dried juice (corresponds to 10-30 milligrams hydroxyanthraquinones) by mouth. As an alternative, in combination with celandine (300 milligrams) and psyllium (50 milligrams), 150 milligrams of the dried juice per day of aloe has been found effective as a laxative in research.
- Cases of death have been associated with Aloe vera injections under unclear circumstances. Injected use is not recommended due to a lack of safety data.
- Other uses of aloe from scientific studies include the treatment of genital herpes (cream applied to lesions for five consecutive days per week for up to two weeks) and psoriasis (cream applied to skin three times per day for five consecutive days per week for up to four weeks).
Children (younger than 18 years)
- Topical (skin) use of aloe gel in children is common and appears to be well tolerated. However a dermatologist and pharmacist should be consulted before starting therapy. Aloe taken by mouth has not been studied in children and theoretically may have harmful effects, such as lowering blood sugar levels. Therefore, it is not recommended.
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Allergies
- People with known allergy to garlic, onions, tulips, or other plants of the Liliaceae family may have allergic reactions to aloe. Individuals using aloe gel for prolonged times have developed allergic reactions including hives and eczema-like rash. Aloe injections have caused severe reactions and should be avoided.
Side Effects and Warnings
- The use of aloe on surgical wounds has been reported to slow healing; redness and burning has been reported after aloe juice was applied to the face after a skin-peeling procedure (dermabrasion). Application of aloe prior to sun exposure may lead to rash in sun-exposed areas.
- The use of aloe or aloe latex by mouth for laxative effects can cause cramping or diarrhea. Use for over seven days may cause dependency or worsening of constipation after the aloe is stopped. Ingestion of aloe for over one year has been reported to increase the risk of colorectal cancer. Individuals with severe abdominal pain, appendicitis, ileus (temporary paralysis of the bowel), or a prolonged period without bowel movements should not take aloe. There is a report of hepatitis (liver inflammation) with the use of oral aloe.
- Electrolyte imbalances in the blood, including low potassium levels, may be caused by the laxative effect of aloe. This effect may be greater in people with diabetes or kidney disease. Low potassium levels can lead to abnormal heart rhythms or muscle weakness. People with heart disease, kidney disease, or electrolyte abnormalities should not take aloe by mouth. Healthcare professionals should watch for changes in potassium and other electrolytes in individuals who take aloe by mouth for more than a few days.
- Aloe taken by mouth may lower blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a healthcare professional, and medication adjustments may be necessary. People with thyroid disorders, kidney disease, heart disease, or electrolyte abnormalities should also use oral aloe only under medical supervision.
- Avoid Aloe vera injections, which have been associated with cases of death under unclear circumstances.
Pregnancy and Breastfeeding
- Although topical (skin) use of aloe is unlikely to be harmful during pregnancy or breastfeeding, oral (by mouth) use is not recommended due to theoretical stimulation of uterine contractions. It is not known whether active ingredients of aloe may be present in breast milk. The dried juice of aloe leaves should not be consumed by breastfeeding mothers.
Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.
Interactions with Drugs
- Aloe taken by mouth may lower blood sugar levels. Caution is advised when taken with medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or injection should be monitored closely by a qualified healthcare professional. Medication adjustments may be necessary. In addition, insulin may add to the decrease in blood potassium levels that can occur with aloe.
- Due to the lowering of potassium levels that may occur when aloe is taken by mouth, the effectiveness of heart medications such as digoxin and digitoxin, and of other medications used for heart rhythm disturbances, may be reduced. The risk of adverse effects may be increased with these medications due to low potassium levels.
- Caution should be used in patients taking loop diuretics, such as Lasix® (furosemide), or thiazide diuretics, such as hydrochlorothiazide (HCTZ), that increase the elimination of both fluid and potassium in the urine. Combined use may increase the risk of potassium depletion and of dehydration.
- Use of aloe with laxative drugs may increase the risk of dehydration, potassium depletion, electrolyte imbalance, and changes in blood pH. Due to its laxative effect, aloe may also reduce the absorption of some drugs.
- Application of aloe to skin may increase the absorption of steroid creams such as hydrocortisone. In addition, oral use of aloe and steroids such as prednisone may increase the risk of potassium depletion.
- There is one report of excess bleeding in a patient undergoing surgery receiving the anesthetic drug sevoflurane, who was also taking aloe by mouth. It is not clear that aloe or this specific interaction was the cause of bleeding.
- Preliminary reports suggest that levels of AZT, a drug prescribed in HIV infection, may be increased by intake of aloe.
- Drugs used for cancer and for hormone activity (hormone replacement therapy, birth control pills) may also interact with aloe.
Interactions with Herbs and Dietary Supplements
- Based on the laxative properties of oral aloe, prolonged use may result in potassium depletion. Aloe may increase the potassium-lowering effects of other herbs such as licorice ( Glycyrrhiza glabra ). Theoretically, use of oral aloe and other laxative herbs such as senna may increase the risk of dehydration, potassium depletion, electrolyte imbalance, and changes in blood pH.
- Oral aloe can reduce blood sugar. Caution is advised when using herbs or supplements such as bitter melon that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.
- Herbs and supplements used for cancer or the heart may interact with aloe. Phytoestrogens such as soy, as well as antivirals may also interact with aloe. Aloe may increase the absorption of vitamin C and vitamin E.
- This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com): Jennifer Armstrong, PharmD (University of Rhode Island); Ethan Basch, MD (Memorial Sloan-Kettering Cancer Center); Samuel Basch, MD (Mt. Sinai Medical Center, NY); Steve Bent, MD (University of California, San Francisco); Dawn Costa, BA, BS (Natural Standard Research Collaboration); Cynthia Dacey, PharmD (Northeastern University); Sean Dalton, MD, PhD, MPH (Harvard University); Ivo Foppa, MD, ScD (Harvard University); Paul Hammerness, MD (Harvard Medical School); Jenna Hollenstein, MS, RD (Natural Standard Research Collaboration); Catherine Kirkwood, MPH, CCCJS-MAC (MD Anderson Cancer Center, University of Texas); David Sollars, M.Ac, H.M.C. (New England School of Acupuncture); Shaina Tanguay-Colucci, BS (Natural Standard Research Collaboration); Catherine Ulbricht, PharmD (Massachusetts General Hospital); Wendy Weissner, BA (Natural Standard Research Collaboration).
Methodology details
- Dal'Belo SE, Gaspar LR, Maia Campos PM. Moisturizing effect of cosmetic formulations containing Aloe vera extract in different concentrations assessed by skin bioengineering techniques. Skin Res Technol. 2006;12(4):241-6.
- Ernst E, Pittler MH, Stevinson C. Complementary/alternative medicine in dermatology: evidence-assessed efficacy of two diseases and two treatments. Am.J.Clin.Dermatol. 2002;3(5):341-348.
- Heggie S, Bryant GP, Tripcony L, et al. Phase III study on the efficacy of topical aloe vera gel on irradiated breast tissue. Cancer Nurs 2002;25(6):442-451.
- Kim EJ, Kim HJ, Kim SG, et al. Aloe-induced Henoch-Schonlein purpura. Nephrology (Carlton). 2007;12(1):109.
- Langmead L, Feakins RM, Goldthorpe S, et al. Randomized, double-blind, placebo-controlled trial of oral aloe vera gel for active ulcerative colitis. Aliment.Pharmacol.Ther. 4-1-2004;19(7):739-747.
- Lee A, Chui PT, Aun CS, et al. Possible interaction between sevoflurane and Aloe vera. Ann Pharmacother. 2004;38(10):1651-1654.
- Montaner JS, Gill J, Singer J, et al. Double-blind placebo-controlled pilot trial of acemannan in advanced human immunodeficiency virus disease. J Acquir Immune Defic Syn Hum Retrovirol 1996;12:153-157.
- Natural Standard Research Collaboration, Chief Editors: Ulbricht C, Basch E, Natural Standard Herb and Supplement Reference - Evidence-Based Clinical Reviews, USA: Elsevier/Mosby, 2005.
- Rabe C, Musch A, Schirmacher P, et al. Acute hepatitis induced by an Aloe vera preparation: a case report. World J Gastroenterol. 1-14-2005;11(2):303-304.
- Schmidt JM, Greenspoon JS. Aloe vera dermal wound gel is associated with a delay in wound healing. Obstetrics & Gynecology 1991;78(1):115-117.
- Su CK, Mehta V, Ravikumar L, et al. Phase II double-blind randomized study comparing oral aloe vera versus placebo to prevent radiation-related mucositis in patients with head-and-neck neoplasms. Int.J Radiat.Oncol.Biol.Phys. 9-1-2004;60(1):171-177.
- Syed TA, Cheema KM, Ahmad SA, et al. Aloe vera extract 0.5% in hydrophilic cream versus aloe vera gel for the measurement of genital herpes in males. A placebo-controlled, double-blind, comparative study. Journal of the European Academy of Dermatology & Venerology 1996;7(3):294-295.
- Syed TA, Afzal M, Ashfaq AS. Management of genital herpes in men with 0.5% Aloe vera extract in a hydrophilic cream. A placebo-controlled double-blind study. J Derm Treatment 1997;8(2):99-102.
- Vardy AD, Cohen AD, Tchetov T. A double-blind, placebo-controlled trial of Aloe vera (A. barbadensis) emulsion in the treatment of seborrheic dermatitis. J Derm Treatment 1999;10(1):7-11.
- Vogler BK, Ernst E. Aloe vera: a systematic review of its clinical effectiveness. Br.J Gen.Pract. 1999;49(447):823-828.
February 01, 2008.
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This evidence-based monograph was prepared by the Natural Standard Research Collaboration. The information provided should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. Talk to your health care provider before taking any prescription or over the counter drugs (including any herbal medicines or supplements) or following any treatment or regimen. Copyright© 2009 Natural Standard (www.naturalstandard.com). All Rights Reserved.
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