Echinacea (E. angustifolia DC, E. pallida, E. purpurea)
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| Echinacea |
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Echinacea species are perennials which belong to the Aster family and which
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
U.S., sales of echinacea are believed to represent approximately 10% of the
dietary supplement market.
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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 E.
purpurea and E. angustifolia . Another clinical
trial reported in July 2005 did not demonstrate any clinical benefit either.
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 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.
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For URI prevention (prophylaxis), daily echinacea has not
been shown effective in human trials.
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Preliminary studies of echinacea taken by mouth for genital herpes and
radiation-associated toxicity remain inconclusive. Topical E.
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.
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The German Commission E discourages use of echinacea in patients with
autoimmune diseases, but this warning is based on theoretical considerations
rather than human data.
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American coneflower, black Sampson, black Susan, cock-up-hat, combflower,
Echinacin®, Echinaforce®, Echinaguard®, hedgehog, igelkopf, Indian head,
Kansas snake root, kegelblume, narrow-leaved purple coneflower, purple
coneflower, red sunflower, rudbeckia, 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* |
| Cancer
There is no clear human evidence of the effects of echinacea on any type
of cancer.
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C |
| 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.
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| Low white blood cell counts after X-ray treatment
Studies have reported mixed results, and it is not clear whether
echinacea has benefits for this use.
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| 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.
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C |
| 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.
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C |
| Genital herpes
Initial human studies suggest that echinacea is not helpful in the
treatment of genital herpes.
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| 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.
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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.
Abscesses, acne, attention deficit hyperactivity disorder (ADHD), bacterial
infections, bee stings, boils, burn wounds, cold sores, diphtheria, dizziness,
eczema, gingivitis, hemorrhoids, HIV/AIDS, malaria, menopause, migraine
headache, nasal congestion/runny nose, pain, psoriasis, rheumatism, skin ulcers,
snake bites, stomach upset, syphilis, tonsillitis, typhoid, urinary tract
infections, whooping cough (pertussis), yeast infections.
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)
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Capsules (of powdered herb): For treatment of upper respiratory tract
infections, 500 to 1,000 milligrams by mouth three times daily for five to
seven days has been used.
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Expressed juice: 6 to 9 milliliters by mouth daily, divided into two or three
doses, for five to seven days has been used.
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Extract: 300 milligrams of E. purpurea extract by mouth
three times daily, 300 milligrams of E. angustifolia root
extract three times daily, or E. purpurea above-ground
plant parts three times daily (176 milligrams EchinaGuard® [Echinacin®]
Madaus GmbH) has been found effective in the prevention and/or treatment of
colds although more research is needed to confirm these results.
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Tincture (1:5): 0.75 to 1.5 milliliters, gargled then swallowed, two to five
times daily for five to seven days has been used (daily dose equivalent to 900
milligrams dried echinacea root). Some herbalists prefer tinctures due to
theoretical immune stimulation in the tonsils when tinctures are gargled
before swallowing.
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Tea: Two teaspoons of coarsely powdered herb (4 grams of echinacea) in one cup
of boiling water for 10 minutes, drink daily for five to seven days, is a dose
that has been used. There is early evidence that echinacea tea (equivalent of
1.275 milligrams of dried herb and root per tea bag) may reduce the symptoms
of upper respiratory tract infection when 5 to 6 cups are taken on the first
day and decreased by 1 cup each day for the next five days.
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Applied to skin (semisolid preparation): 15% pressed herb (non-root) juice
semisolid preparation has been applied daily for wounds and skin ulcers.
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Injected/through the veins: Injected echinacea is not available commercially.
Severe reactions to injected echinacea have been reported, and echinacea
injections are not recommended.
Children (younger than 18 years)
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The dosing and safety of echinacea have not been studied thoroughly in
children. Reductions of recommended adult doses by 50-67% have been used in
research without significant effects in the treatment of common cold symptoms,
and an association with rash development. Parents considering echinacea for
their children should discuss this decision with the child's health care
provider before starting therapy. Some natural medicine practitioners
recommend basing children's doses based on weight. To calculate the child's
dose, they take the child's weight in pounds, divide by 150, and then multiply
that number by the recommended adult dose.
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
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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.
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Echinacea has been associated with an increased incidence of rash in children,
and therefore the risks of use may outweigh potential benefits.
Side Effects and Warnings
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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.
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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 are no 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).
Pregnancy and Breastfeeding
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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
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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.
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In theory, echinacea's ability to stimulate the immune system may interfere
with drugs that are taken to suppress the immune system (including
azathioprine, cyclosporine, and steroids such as prednisone). No clear human
studies are available.
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In one vague report, a person taking the antibiotic amoxicillin and an unclear
echinacea preparation developed muscle damage, shock, and death.
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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.
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Many tinctures contain high levels of alcohol, and may cause nausea or
vomiting when taken with metronidazole (Flagyl®) or disulfiram (Antabuse®).
Interactions with Herbs and Dietary Supplements
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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. Echinacea may affect the way certain herbs and supplements are broken
down by the liver.
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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. No high quality human studies have shown added benefits
or interactions of these combinations.