Sources: Echinacea, also known as purple coneflower, is the root or aboveground parts (harvested in flower) of three species of large, robust daisylike plants of the aster family. E. angustifolia and E. pallida are harvested from the prairies of the midwestern United States. Some commercial cultivation of these two species has developed as they have become more scarce in the wild. E. purpurea, also native to the Midwest, is the most widely used species of the three. The entire world supply is cultivated.

Traditional Use: Native Americans of the prairie used echinacea for more medicinal purposes than they did any other plant, for everything from colds to cancer. It entered formal medicine in 1895, becoming the best-selling American medicinal plant prescribed by physicians into the 1920s. Later replaced by antibiotics in the United States, it has enjoyed continuous popularity in Europe. In 1993 German physicians prescribed echinacea more than 2.5 million times. Traditionally, herbalists consider it a blood purifier and aid to fighting infections.

Current Use: Today most consumers use echinacea to prevent and treat colds and to help heal infections. Echinacea enhances the particle-ingestion capacity of white blood cells and other specialized immune-system cells, increasing their ability to attack foreign invaders such as cold or flu viruses. Besides stimulating a healthy immune system to deal more effectively with invading viruses, echinacea helps accelerate healing if infection already exists.

A 1992 German double-blind, placebo-controlled study of 180 volunteers using E. purpurea found that a dose of 4 droppers of tincture (equivalent to 900 mg of dried root) decreased symptoms and duration of flu-like infections. The best-studied form of echinacea is a preparation made from the fresh expressed juice of E. purpurea. No single chemical component has been identified as causing echinacea's medicinal action. A 1997 controlled clinical study on 120 volunteers in Sweden showed that daily treatment with the juice of fresh flowering E. purpurea at the first sign of cold symptoms inhibited development of colds, and if a cold was in progress, it cut the duration in half. More clinical studies are needed to determine clear therapeutic indications, the best preparations, and the most effective dosage.

AT-A-GLANCE

Used For: Colds * Flu * Minor infections Preparations: Dried whole herb or root; capsules, expressed juice of fresh flowering plant, flex-tabs, tablets, tea, tinctures. Some products are standardized to echinacoside despite the fact the compound has not been found to stimulate the immune system. Typical Dosages: Capsules: Up to nine 300-400 mg capsules a day. Tincture: 60 drops 3 times a day. This is equivalent to 1 g of dried root a day. Use as needed at the onset of symptoms of cold or flu. Take continuously for two weeks, followed by a resting period of one week. Or follow manufacturer's or practitioner's recommendations. Cautions: Persons who are allergic to the pollen of other members of the aster family, such as ragweed, may also be allergic to echinacea. The German government recommends that nonspecific immunostimulants, including echinacea, should not be used in cases of impaired immune response involving diseases of the immune system itself, including tuberculosis, multiple sclerosis, and HIV infection. This finding is based on the concept that immunostimulants should not be used when autoimmune disease is present.

References

Bauer R. and H. Wagner, 1991. "Echinacea Species as Potential Immunostimulatory Drugs." In Economic and Medicinal Plant Research (Vol. 5). Orlando: Academic Press.

Braunig, B. et al. 1992. "Echinacea purpurea radix for Strengthening the Immune Response in Flu-like Infections." Zeitchrift fur Phytotherapie 13:7-13.

Foster, S. 1991. Echinacea: Nature's Immune Enhancer. Rochester, VT: Healing Arts Press.

Melchart, D. et al. 1994. "Immunomodulation with Echinacea - A Systematic Review of Controlled Clinical Studies." Phytomedicine 1: 245-54.

See, D. M. et al. 1997. "In vitro Effects of Echinacea and Ginseng on Natural Killer and Antibody-dependent Cell Cytotoxicity in Healthy Subjects and Chronic Fatigue Syndrome or Acquired Immunodeficiency Syndrome Patients." Immunopharmacology 35:229-35.