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Echinacea is a perennial plant native to North America that is farmed in both the United States and Europe for use in dietary supplements. Echinacea is a genus in the aster family containing nine plant species. Three species, Echinacea angustifolia, E. purpurea, and E. pallida are used in complementary and alternative medicine in the United States and Europe.
Echinacea species are commonly called cone-flowers. The common name for E. purpurea is purple coneflower. E. pallida is known as pale purple cone-flower and E. angustifolia as narrow-leaf coneflower. Echinacea is sold as an herbal dietary supplement under a variety of trade names. It is also a common ingredient in many supplements containing multiple ingredients.
Echinacea has been used as a medicinal herb in North America for more than 400 years. Native Americans used echinacea to treat wounds, snakebites, infections, and as a general booster of health. In the 1930s the herb was very popular in both the United States and Europe, as it was thought to fight infection by boosting the immune system. It was used to treat conditions as diverse as colds, influenza, eczema, many different types of infections, malaria, syphilis, cancer, and diphtheria. As antibiotics became more widely available after World War II, echinacea’s popularity declined, only to rise again in the 1980s. It is one of the most frequently used herbal remedies in the North America and Europe. Echinacea is especially popular in Germany, where many practitioners of conventional medicine accept it as a safe and effective treatment for cold symptoms. In 2003, echinacea was one of the top three selling herbs in the United States, and in 2006 it was estimated to account for 10% of all dietary supplement sales in the United States.
Echinacea is a perennial herb with slender, rough leaves arranged opposite each other on a stem that grows to a height of about 18 in (45 cm) and produces a single large purplish flower. Both the above ground parts of the plant and the roots are used in dietary supplements. Fresh leaves are pressed and the resulting juice is used in extracts or tinctures, or it is combined with other ingredients to make a paste that can be applied to the skin. Dried leaves and roots are Echinacea flowers, also called purple coneflowers.
powered and made into tea or capsules. An injectable form of echinacea is available in Europe, but not in the United States. The active ingredients of echinacea have not been adequately identified. As a result, it is difficult to compare the strength and potency of different forms of the herb or the same formulation made by different manufacturers.
Safety and effectiveness of Echinacea
Although echinacea has been used for hundreds of years, only recently have researchers started to examine its effectiveness in large, independent, rigorously controlled studies. Many early studies done in Germany suggested that the herb was effective in treating certain conditions. In the United States, the National Center for Complementary and Alternative Medicine (NCCAM), a government organization within the National Institutes of Health, is currently conducting studies on the safety and effectiveness of echinacea in treating a variety of conditions.
In the United States, the Food and Drug Administration (FDA) regulates dietary supplements such as echinacea using the same laws that regulate food, rather than the laws that regulate prescription and over-the-counter medications. Unlike conventional drugs, dietary supplements are not required to undergo rigorous testing to show that they are safe and effective before they are marketed to the public. One consequence of this is that there are many fewer
studies of dietary supplements, and some of those studies are sponsored by the manufacturers who have an economic investment in positive outcomes. Too often, studies of dietary supplements are small, poorly designed, poorly controlled, or incompletely reported, making it is difficult to draw hard conclusions about the effectiveness and safety of the product.
The most common use of echinacea in the United States and Europe is to prevent or shorten and reduce the severity of symptoms of the common cold, including sneezing, runny, nose, cough, and fever. Natural Standard, an independent organization that evaluates studies, scientific evidence, and expert opinion on complementary and alternative treatments and makes impartial judgments concerning their safety and effectiveness has found that the evidence of effectiveness of echinacea in treating cold symptoms is mixed. Some studies have shown that individuals who take echinacea during cold season are less likely to catch a cold, but more have found that echinacea has no effect on whether an individual catches a cold. On the other hand, more than half of a substantial number of well-designed European studies found that people who take echinacea at the first sign of a cold feel better sooner than those who take a placebo or who take nothing. These results have been contradicted by several large, well-designed American studies, including one in 2005 of children ages 2-11 that found on average echinacea did not reduce the length of time the children showed cold symptoms. Two studies sponsored by NCCAM also found echinacea did not shorten the symptoms of colds or influenza or prevent colds.
For years, echinacea has been taken to improve general health and to treat a variety of infections because it is thought to boost the immune system. Laboratory analyses of the ingredients in echinacea and some animal studies have suggested that echinacea does stimulate immune system cells. However, this result has not been confirmed in humans. Research continues on this use of echinacea.
Claims have also been made that individuals with AIDS, cancer, and genital herpes can benefit from taking echinacea. Although there is some theoretical basis for these claims, there is no clear evidence that echinacea has an effect on these conditions in humans.
Despite mixed evidence about the effectiveness of echinacea, the herb generally appears to be safe when taken by adults in moderate amounts. There is no standardization of the amount of active ingredient in products containing echinacea. Guidelines of normal doses for a 150 lb (70 kg) adult taken three times a day are:
- 1-2 g dried leaves or root brewed into tea
- 2-3 mL tincture
- 200 mg powdered extract
Lower doses of echinacea for children, based on the weight of the child, are generally thought to be safe, although in the cold study mentioned above, children showed an increased risk of developing a rash. One study of pregnant women using echinacea found that moderate use of the herb during the first three months of pregnancy did not increase the likelihood of the baby being born with major birth defects. The safety of echinacea use in breastfeeding women has not been adequately studied.
Individuals interested in taking echinacea should consult their health care provider and other reputable sources of information before starting the herb. Pregnant or breastfeeding women should be especially careful to discuss the use of echinacea and all other drugs and supplements with their health care provider. One animal study indicated that the increase in white blood cells normally seen during pregnancy was reduced or eliminated in women who took echinacea during pregnancy. This suggests that women who should avoid the drug during pregnancy. A separate study designed to evaluate the safety of echinacea during pregnancy failed to show any harm to either the mother or the fetus. In addition, care should be taken in giving children echinacea. Few studies have been done specifically on children.
As with any medication, more is not necessarily better, and the words “natural” or “organic” on the label do not mean the product is safe. Overdose can cause serious side effects. In the event of side effects, echinacea should be stopped immediately and the side effects reported to a health care professional. People with autoimmune diseases (e.g., AIDS, multiple sclerosis) are often counseled to avoid echinacea, because of theoretical, but unproven, negative effects on the immune system.
Echinacea may interact with both conventional drugs and other herbs or dietary supplements, but few rigorous studies have been done on potential interactions. Individuals should tell their health care provider about all the conventional drugs and dietary supplements they are taking before beginning any new drug or supplement.
Since echinacea may stimulate the immune system, it is recommended that individuals who are taking immune system suppressant drugs following cancer treatment or organ transplant avoid echinacea. This interaction has not been verified experimentally, and some trials suggest that echinacea can actually benefit cancer patients.
Echinacea may also interact with econazole, an antifungal drug. Individuals who take echinacea while taking econazole to treat fungal infections appear more likely to have reoccurrence of the fungal infection.
People who are allergic to ragweed, chrysanthemums, marigolds, daisies, and related plants have a greater chance of being allergic to echinacea. Allergic reactions have on rare occasions been reported to be severe and cause breathing difficulties, especially in people with asthma. Much more common are allergic reactions consisting of a rash, sneezing, or runny nose.
Parents should be aware that the safe dose of many herbal supplements has not been established for children. Accidental overdose may occur if children are give adult herbal supplements.
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Tish Davidson, A.M.