IMAGE Many people who become interested in herbs and natural remedies began with an introduction to echinacea, an herbal remedy commonly used for treating colds. Does it really work?

What Is It?

Echinacea is a perennial plant that grows 1-2 feet (0.3-0.6 meters) in height and looks something like a Black-eyed Susan. Grown both commercially and in the wild, its flower, stem, and root are marketed in pill, liquid, or powdered form.

What Is the Background on It?

Originally, echinacea was used by many Midwest Native Americans for a variety of medicinal purposes, including the treatment of infections and poisonous snakebites. As early as the 1880s, echinacea came into favor among American medical practitioners. Despite the fact that in 1910 the American Medical Association dismissed echinacea as worthless, it remained popular in the United States until penicillin and other anti-infection drugs were discovered.

In the 1930s, a German doctor, Gerhard Madaus, began researching the medicinal properties of echinacea. He discovered that it contained certain complex sugar molecules, known as polysaccharides, which he believed might stimulate the immune system. Dr. Madaus also developed a juice form of echinacea that was derived from the plant's flower.

What Is It Used for?

While echinacea has been promoted as a substance that can stimulate the immune system, this action has not been proven. There is no evidence that echinacea strengthens the immune system when taken over the long term.

However, studies do support the use of echinacea as a treatment for colds and flu. The herb, taken at the first sign of illness, may reduce your symptoms and help you recover faster. It does not seem, though, that daily doses of echinacea will prevent you from getting sick. Echinacea has been studied for other infections, as well, like chronic bronchitis and ear infections, but more research needs to be done in these areas.

How Does It Work?

While it is not clear exactly how echinacea works, some evidence hints that echinacea acts by doing the following:

  • Stimulating phagocytosis, the process by which white blood cells and lymphocytes consume (and thus destroy) foreign organisms in the body
  • Increasing the rate at which the immune system ejects foreign organisms from the body
  • Increasing the number of cells working as part of the immune system
  • Increasing the production of interferon, a major component of the body's immune system

How Should You Use It?

Echinacea is taken at the first sign of a cold or flu and continued for 1-2 weeks. The best tested formulations are extracts made from the above-ground parts of the Echinacea purpurea species. Echinacea purpurea root alone may not be effective. Follow label instructions for dosage. The effectiveness of other echinacea species including E. pallida and E. angustifolia has not been established.

What Are the Side Effects?

Echinacea has not shown significant side effects in studies but mild limited side effects have been noted, including allergic reactions such as rashes and increased asthma. Other side effects include minor gastrointestinal symptoms, increased urination, and mild allergic reactions. People allergic to plant families such as the daisy or sunflower should talk with their doctor before using echinacea.

When Should Echinacea Be Avoided?

However, if in fact echinacea stimulates the immune system, it could theoretically cause harm in people with certain conditions. These include the following:

Finally, it has also been suggested that women should avoid taking echinacea while pregnant.

Regulation of Echinacea

Since echinacea is a natural growing compound, it is covered by the Dietary Supplement Health and Education Act (DSHEA) and is not regulated by the United States Food and Drug Administration (FDA). DSHEA mandates that the label of a dietary supplement must contain enough information about the composition of the product so that consumers can make informed choices. The information must be presented in the FDA-specified format.

The manufacturer is also responsible for making sure that all the dietary ingredients in the supplements are safe. Manufacturers and distributors do not need to register with the FDA or get FDA approval before producing or selling dietary supplements, nor is its use or effectiveness substantiated by the FDA.