The Whole Truth About Echinacea

The Whole Truth About Echinacea

With cold and flu season right around the corner, you’ll be hearing a lot about herbal substances that may prevent you and your family from being miserable this flu season. Echinacea is one of the most popular herbal treatments to help prevent cold/flu symptoms. Don’t you think it’s about time to find out the whole truth?

This report provides basic information about the herb echinacea--common names, uses, potential side effects, and resources for more information. There are nine known species of echinacea, all of which are native to the United States and southern Canada. The most commonly used, Echinacea purpurea, is believed to be the most potent.

Common Names--echinacea, purple coneflower, coneflower, American coneflower

Latin Names--Echinacea purpurea, Echinacea angustifolia, Echinacea pallida

What It Is Used For

Echinacea has traditionally been used to treat or prevent colds, flu, and other infections. Echinacea is believed to stimulate the immune system to help fight infections. Less commonly, echinacea has been used for wounds and skin problems, such as acne or boils.

How It Is Used

The aboveground parts of the plant and roots of echinacea are used fresh or dried to make teas, squeezed (expressed) juice, extracts, or preparations for external use.

What the Science Says

Studies indicate that echinacea does not appear to prevent colds or other infections. Studies to date have not proven that echinacea shortens the course of colds or flu. For example, two NCCAM-funded studies did not find a benefit from echinacea, either as Echinacea purpurea fresh-pressed juice for treating colds in children, or as an unrefined mixture of Echinacea angustifolia root and Echinacea purpurea root and herb in adults. Other studies have shown that echinacea may be beneficial in treating upper respiratory infections. NCCAM is continuing to support the study of echinacea for the treatment of upper respiratory infections.

Side Effects and Cautions

When taken by mouth, echinacea usually does not cause side effects. However, some people experience allergic reactions, including rashes, increased asthma, and anaphylaxis (a life-threatening allergic reaction). In clinical trials, gastrointestinal side effects were most common. People are more likely to experience allergic reactions to echinacea if they are allergic to related plants in the daisy family, which includes ragweed, chrysanthemums, marigolds, and daisies. Also, people with asthma or atopy (a genetic tendency toward allergic reactions) may be more likely to have an allergic reaction when taking echinacea. It is important to inform your health care providers about any herb or dietary supplement you are using, including echinacea. This helps to ensure safe and coordinated care.

Study Results Say That Echinacea Is Not Effective in Treating Children's Colds

Researchers at the University of Washington and Bastyr University have found that echinacea (Echinacea purpurea), an herb often used to treat colds (upper respiratory infections), is not effective in young children. The researchers reported that use of echinacea from the onset of symptoms did not lessen the number of days the colds lasted or the severity of symptoms.

The study, published in the Journal of the American Medical Association, enrolled 524 children aged 2 to 11. The children were randomly assigned to receive either echinacea or a placebo at the onset of cold symptoms and twice a day for as long as the cold lasted, up to a maximum of 10 days. The echinacea preparation was a dried-pressed juice of the herb that had been used previously in a number of encouraging preliminary studies in Europe. Participants were enrolled for 4-month intervals and received treatment for up to three colds during that period. Data were analyzed for 707 colds (337 treated with echinacea and 370 treated with placebo) experienced by 407 children.

Overall, the researchers found that between those receiving echinacea and those receiving placebo at the onset of symptoms there was:
* No difference in the duration of upper respiratory infection symptoms
* No difference in the overall severity of symptoms
* No difference in the number of days of fever
* No difference in parents' assessment of severity of infection
* No overall difference in side effects (adverse events); however, children taking echinacea were more likely to develop rashes than those taking placebo.

The researchers concluded that the "results do not support the use of echinacea for treatment of upper respiratory infections in children 2 to 11 years old." In addition, the researchers recommend more studies to look at other echinacea preparations or different doses or dosing schedules to determine if there is any possible role for echinacea in treating colds in children. They also suggest further research to determine whether echinacea has any role in preventing colds.

Echinacea species are flowering herbs native to North America. Echinacea is often used by consumers for the treatment and prevention of upper respiratory infections. It is one of the most commonly used herbs in the United States.

Echinacea for the Prevention and Treatment
of Colds in Adults

On July 28, 2005, The New England Journal of Medicine published the results of a study of Echinacea for the prevention and treatment of the common cold that was funded by the National Center for Complementary and Alternative Medicine (NCCAM). The research was conducted by Dr. Ronald Turner, of the University of Virginia School of Medicine, Dr. Rudolf Bauer, Karl-Franzens Universitaet, Graz, Austria, and collaborators at Clemson University in South Carolina.

The research team tested three preparations of the roots of a species of Echinacea called Echinacea angustifolia, which prior smaller studies had found to benefit adults with the common cold. The three preparations were made by extracting the root of E. angustifolia using procedures that represent some of the different ways that Echinacea is available and used to treat the common cold.

E. angustifolia was chosen for the study as it is one of the species endorsed by the World Health Organization for treating the common cold. The study was designed to test if Echinacea would help prevent or treat cold symptoms, since this is how Echinacea is often used by consumers.

In the study, 437 healthy adult volunteers were assigned at random to receive one of the three E. angustifolia preparations or a placebo. The volunteers received various combinations of Echinacea and/or a placebo in two phases: a "prophylaxis" (i.e., preventative) phase and a treatment phase. The prophylaxis phase lasted 7 days. On the seventh day, the already treated volunteers were exposed to a nasal spray containing a virus that induces signs and symptoms of a cold in about 2 days. Then, the volunteers were isolated for 5 days while the research team observed and tested them, using state-of-the-art measurements and instruments, as to the appearance and severity of cold signs and symptoms.

In this study, the researchers found that none of the three preparations of E. angustifolia at the 900 mg per day dose had significant effects on whether volunteers became infected with the cold virus or on the severity or duration of symptoms among those who developed colds. However, critics of this study believe the dose of E. angustifolia used was too low.

Research Design Challenges

Research on botanicals and other natural products presents a number of challenges related to product characterization, standardization, and dosage. For Echinacea, these challenges include:
* determining whether the roots, leaves, flowers, seeds, or stems are the most effective parts of the plant,
* investigating the differences between the major Echinacea species (E. purpurea, E. angustifolia, and E. pallida), and
* determining the proper dose.

It is only after these questions have been answered and standardized preparations have been developed that additional large-scale Phase III clinical trials can be conducted.

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