Echinacea (Echinacea angustifolia DC, Echinacea pallida, Echinacea purpurea)
- Echinacea species are perennials that belong to the Aster family and originate in eastern North America. Traditionally used for a range of infections and malignancies, the roots and herb (above ground parts) of echinacea species have attracted recent scientific interest due to purported "immune stimulant" properties. Oral preparations are popular in Europe and the United States for prevention and treatment of upper respiratory tract infections (URI), and Echinacea purpurea herb is believed to be the most potent echinacea species for this indication. In the United States, sales of echinacea are believed to represent approximately 10% of the dietary supplement market.
- For URI treatment, numerous human trials have found echinacea to reduce duration and severity, particularly when initiated at the earliest onset of symptoms. However, the majority of trials, largely conducted in Europe, have been small or of weak design. Negative results exist of a U.S. trial in adults, which used a whole-plant echinacea preparation containing both Echinacea purpurea and Echinacea angustifolia . Another clinical trial reported in July 2005 also did not demonstrate any clinical benefit. However, a 2006 meta-analysis investigating the efficacy of echinacea found that the likelihood of experiencing a clinical cold was 55% higher with placebo than with Echinacea (based on three trials). The sum of the current evidence is conflicting and further well-designed studies are needed before a definitive conclusion can be drawn. Lack of benefit in children ages 2-11 has also been reported.
- For URI prevention (prophylaxis), daily echinacea has not been shown effective in human trials.
- Preliminary studies of echinacea taken by mouth for genital herpes and radiation-associated toxicity remain inconclusive. Topical Echinacea purpurea juice has been suggested for skin and oral wound healing, and oral/injectable echinacea for vaginal Candida albicans infections, but evidence is lacking in these areas.
- The German Commission E discourages the use of echinacea in patients with autoimmune diseases, but this warning is based on theoretical considerations rather than human data.
- In children, echinacea cannot be recommended due to reports of rash and apparent lack of benefits in the available literature.
- Alkamides, American coneflower, Asteraceae (family), black Sampson, black Susan, cichoric acid, cock-up-hat, combflower, coneflower, Echinacea angustifolia , Echinacea pallida , Echinacea Plus, Echinacea purpurea , Echinacin®, Echinacin® EC31, Echinaforce®, Echinaforce® Forte, Echinaguard®, Echinilin® (Factors R & D Technologies, Burnaby, British Columbia, Canada), hedgehog, igelkopf, Indian head, Kansas snake root, kegelblume, narrow-leaved purple coneflower, Pascotox®, polysaccharides, purple coneflower, red sunflower, rudbeckia, SB-TOX, scurvy root, snakeroot, solhat, sun hat.
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*
|Prevention of upper respiratory tract infections (adults and children)
Preliminary studies suggest that echinacea is not helpful for preventing the common cold in adults. A recent meta-analysis suggested that standardized extracts of echinacea were effective in the prevention of symptoms of the common cold after clinical inoculation, compared with placebo. In children, a combination of echinacea, propolis, and vitamin C has been reported to reduce the number and duration of cold episodes. However, prevention research overall has not been well designed, and additional trials are needed before a clear conclusion can be drawn.
|Treatment of upper respiratory tract infections (adults)
Although multiple low quality studies have previously suggested that taking echinacea by mouth by adults when cold symptoms begin may reduce the length and severity of symptoms, a clinical trial reported in July 2005 did not demonstrate any clinical benefit. Recent meta-analyses are conflicting; one suggested that standardized extracts of echinacea were effective in the prevention of symptoms of the common cold after clinical inoculation, compared with placebo, whereas the other reported no such benefit. Further research is needed.
There is a lack of clear human evidence that echinacea affects any type of cancer.
|Immune system stimulation
Echinacea has been studied alone and in combination preparations for immune system stimulation (including in patients receiving cancer chemotherapy). It remains unclear if there are clinically significant benefits. Additional studies are needed in this area before conclusions can be drawn regarding safety or effectiveness.
|Low white blood cell counts after X-ray treatment (leukopenia)
Studies have reported mixed results, and it is not clear whether echinacea has benefits for this use.
|Uveitis (eye inflammation)
Oral Echinacea purpurea may offer some benefits in people with low-grade uveitis. Further research is needed to confirm these findings.
|Vaginal yeast infections
When echinacea is used at the same time as the prescription cream econazole nitrate (Spectazole®), vaginal yeast infections ( Candida ) may occur less frequently. However, further research is needed to confirm this.
Initial human studies suggest that echinacea is not helpful in the treatment of genital herpes.
|Treatment of upper respiratory tract infections (children)
Initial research suggests that echinacea may not be helpful in children for alleviation of cold symptoms, possibly because parents are not able to recognize the onset of common cold symptoms soon enough to begin treatment, or because the dose of echinacea for use in children is not clear. There are fundamental differences in causes of upper respiratory tract infection symptoms in children versus adults (bacterial versus viral causes, different viruses, different sites of infection, etc). Until additional research is available, echinacea cannot be considered effective in children for this use. Furthermore, development of rash has been associated with echinacea use, and therefore the risks may outweigh the potential benefits in this population.
Uses based on tradition or theory
*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.
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.
Abscesses, acne, attention deficit hyperactivity disorder (ADHD), bacterial infections, bee stings, boils, burn wounds, diphtheria, dizziness, eczema, gingivitis, gum inflammation (pyorrhea), hemorrhoids, herpes labialis, HIV/AIDS, influenza, malaria, menopause, migraine headache, mouth sores, nasal congestion/runny nose, pain, psoriasis, rheumatism, skin ulcers, snake bites, stomach upset, syphilis, tonsillitis, typhoid, urinary disorders, urinary tract infections, whooping cough (pertussis).
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 (over 18 years old)
- There is no proven effective medicinal dose for echinacea. Echinacea is commercially available as capsules, expressed juice, extract, tincture and tea. A common dosing range studied in trials is 500 to 1,000 milligrams of echinacea in capsule form taken by mouth three times daily for five to seven days. As an extract, 300 to 800 milligrams of echinacea has been taken by mouth two to three times daily for up to six months.
- When applied on the skin, echinacea 15% pressed herb (non-root) juice semisolid preparation has been used daily for wounds and skin ulcers. Injected echinacea is not available commercially. Severe reactions to injected echinacea have been reported, and echinacea injections are not recommended.
Children (under 18 years old)
- The dosing and safety of echinacea have not been studied thoroughly in children. Parents considering echinacea for their children should discuss this decision with the child's healthcare provider before starting therapy. Some natural medicine practitioners recommend basing children's doses based on weight. The safety of echinacea injections is not established, and injections are not advised.
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.
- People with allergies to plants in the Asteraceae or Compositae family (ragweed, chrysanthemums, marigolds, daisies) are theoretically more likely to have allergic reactions to echinacea. Multiple cases of anaphylactic shock (severe allergic reactions) and allergic rash have been reported with echinacea taken by mouth. Allergic reactions including itching, rash, wheezing, facial swelling, and anaphylaxis may occur more commonly in people with asthma or other allergies. Echinacea injections have caused severe reactions and are not recommended.
- Echinacea has been associated with an increased incidence of rash in children. Therefore, the risks may outweigh potential benefits, and use in children is not recommended.
Side Effects and Warnings
- Few side effects from echinacea are reported when it is used at the recommended doses. Reported complaints include stomach discomfort, nausea, sore throat, rash (allergic, hives, or painful lumps called "erythema nodosum"), drowsiness, headache, dizziness, and muscle aches. Rare cases of hepatitis (liver inflammation), kidney failure, or irregular heart rate (atrial fibrillation) have been reported in people taking echinacea, although it is not clear that these were due to echinacea itself. Injected echinacea may alter blood sugar levels and cause severe reactions and should be avoided. Echinacea has been associated with an increased incidence of rash in children, and therefore the risks of use may outweigh potential benefits. Thrombotic thrombocytopenic purpura (TTP) has also been reported.
- Some natural medicine experts discourage the use of echinacea by people with conditions affecting the immune system, such as HIV/AIDS, some types of cancer, multiple sclerosis, tuberculosis, and rheumatologic diseases (such as rheumatoid arthritis or lupus). However, there is a lack of specific studies or reports in this area, and the risks of echinacea use with these conditions are not clear. Long-term use of this herb may cause low white blood cell counts (leukopenia).
- Liver transplant patients who consume large amounts of echinacea may have increased liver enzyme activity, which often indicates liver damage. Although the relevance of this is not clear, liver transplant patients should use echinacea cautiously due to its potential hazards.
Pregnancy and Breastfeeding
- At this time, echinacea cannot be recommended during pregnancy or breastfeeding. Although early studies show no effect of echinacea on pregnancy, there is not enough research in this area. Pregnant women should avoid tinctures because of the potentially high alcohol content.
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
- Natural medicine practitioners sometimes caution that echinacea may lead to liver inflammation. There is not clear information from laboratory or human studies in this area. Nonetheless, caution should be used when combining echinacea by mouth with other medications that can harm the liver. Examples of such agents include anabolic steroids, amiodarone, methotrexate, acetaminophen (Tylenol®), and antifungal medications taken by mouth (such as ketoconazole). Echinacea may affect the way certain drugs are broken down by the liver.
- In theory, echinacea's ability to stimulate the immune system may interfere with drugs that suppress the immune system (including azathioprine, cyclosporine, and steroids such as prednisone). Because clear human studies are lacking, people taking these drugs should consult a healthcare professional or pharmacist before using echinacea.
- Based on one vague case report, taking echinacea along with amoxicillin may cause life-threatening reactions. However, the details of this case are not very clear.
- Early information suggests that the use of echinacea with econazole nitrate cream (Spectazole®) on the skin may lower the frequency of vaginal yeast infections after treatment.
- Many tinctures contain high levels of alcohol, and may cause nausea or vomiting when taken with metronidazole (Flagyl®) or disulfiram (Antabuse®).
- Echinacea may also interact with anesthetics, antineoplastics, and caffeine. However, these potential interactions are not fully understood.
Interactions with Herbs and Dietary Supplements
- Natural medicine practitioners sometimes caution that echinacea may lead to liver inflammation. Although there is no clear information from laboratory or human studies, in theory echinacea may add to liver toxicity caused by other agents, such as kava. Echinacea may affect the way certain herbs and supplements are broken down by the liver.
- Echinacea is sometimes used in combination products that are thought to stimulate the immune system. For example, Esberitox® (PhytoPharmica, Germany) contains Echinacea purpurea , Echinacea pallida , wild indigo root ( Baptisia tinctoria ), and thuja (white cedar). Echinacea may be combined with goldenseal or other herbs in some cold relief preparations. There is a lack of high-quality human studies that have shown added benefits or interactions of these combinations.
- Echinacea is sometimes sold in combination with goldenseal ( Hydrastis canadensis ), an herb that may reduce the body's ability to absorb vitamin B.
- Anesthetics, antineoplastics, antioxidants, and caffeine may interact with echinacea. However, these potential interactions are not fully understood.
- This information is based on a professional level monograph edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com): Ethan Basch, MD (Memorial Sloan-Kettering Cancer Center); Samuel Basch, MD (Mt. Sinai Medical Center, NY); Wendy Chao, PhD (Natural Standard Research Collaboration); Dawn Costa, BA, BS (Natural Standard Research Collaboration); Sean Dalton, MD, MPH, PhD; Edzard Ernst, MD, PhD (University of Exeter); Ivo Foppa, MD, ScD (Harvard University); Dana A. Hackman, BS (Northeastern University): Carolyn Williams Orlando, MA; Philippe Szapary, MD (University of Pennsylvania); Shaina Tanguay-Colucci, BS (Natural Standard Research Collaboration); Natasha Tiffany, MD (Harvard Medical School); Catherine Ulbricht, PharmD (Massachusetts General Hospital); Mamta Vora, PharmD (Northeastern University); Wendy Weissner, BA (Natural Standard Research Collaboration).
- Barak V, Birkenfeld S, Halperin T, et al. The effect of herbal remedies on the production of human inflammatory and anti-inflammatory cytokines. Isr Med Assoc J 2002;4(11 Suppl):919-922.
- Cohen HA, Varsano I, Kahan E, et al. Effectiveness of an herbal preparation containing echinacea, propolis, and vitamin C in preventing respiratory tract infections in children: a randomized, double-blind, placebo-controlled, multicenter study. Arch Pediatr Adolesc Med 2004;158(3):217-221.
- Gillespie EL, Coleman CI. The effect of Echinacea on upper respiratory infection symptom severity and quality of life. Conn Med 2006 Feb;70(2):93-7.
- Goel V, Lovlin R, Barton R, et al. Efficacy of a standardized echinacea preparation (Echinilin) for the treatment of the common cold: a randomized, double-blind, placebo-controlled trial. J Clin Pharm Ther 2004;29(1):75-83.
- Kemp DE, Franco KN. Possible leukopenia associated with long-term use of echinacea. J Am Board Fam Pract 2002;15(5):417-419.
- Koenig K, Roehr CC. Does treatment with Echinacea purpurea effectively shorten the course of upper respiratory tract infections in children? Arch Dis Child 2006 June; 91(6):535-7.
- Le Tourneau M. Echinacea fails to show efficacy in treating colds in a pediatric population. Altern Ther Health Med 2004;10(1):16.
- Linde K, Barrett B, Wolkart K, et al. Echinacea for preventing and treating the common cold. Cochrane Database Syst Rev 2006 Jan 25;(1):CD000530.
- Lindenmuth GF, Lindenmuth EB. The efficacy of echinacea compound herbal tea preparation on the severity and duration of upper respiratory and flu symptoms: a randomized, double-blind placebo-controlled study. J Altern Complement Med. 2000;6(4):327-334.
- Narimanian M, Badalyan M, Panosyan V, et al. Randomized trial of a fixed combination (KanJang) of herbal extracts containing Adhatoda vasica, Echinacea purpurea and Eleutherococcus senticosus in patients with upper respiratory tract infections. Phytomedicine 2005 Aug;12(8):539-47.
- Neff GW, O'Brien C, Montalbano M, et al. Consumption of dietary supplements in a liver transplant population. Liver Transpl 2004;10(7):881-885.
- Schoop R, Klein P, Suter A, et al. Echinacea in the prevention of induced rhinovirus colds: a meta-analysis. Clin Ther 2006;28(2):174-183.
- Taylor JA, Weber W, Standish L, et al. Efficacy and safety of echinacea in treating upper respiratory tract infections in children: a randomized controlled trial. JAMA 12-3-2003;290(21):2824-2830.
- Turner RB, Bauer R, Woelkart K, et al. An evaluation of Echinacea angustifolia in experimental rhinovirus infections. N Engl J Med 2005 Jul 28;353(4):341-8.
- Vonau B, Chard S, Mandalia S, et al. Does the extract of the plant Echinacea purpurea influence the clinical course of recurrent genital herpes? Int J STD AIDS 2001;12(3):154-158.
March 01, 2008.
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© 2008 Natural Standard (www.naturalstandard.com). All Rights Reserved.