Echinacea is a perennial wildflower containing a variety of biologically active substances. Various parts of the plant are used medicinally.
(See also Overview of Dietary Supplements.)
People take echinacea mostly to help prevent or treat viral infections in the upper respiratory tract, such as the common cold. Well-designed studies have suggested effectiveness for prevention, but not treatment. Some people apply echinacea as a cream or ointment to treat skin disorders and promote healing of wounds.
Echinacea may interact with drugs that can cause liver damage, thereby increasing the risk of liver damage. Echinacea may negate the beneficial effects of immunosuppressants, which are used, for example, to prevent rejection of organ transplants. People who have autoimmune diseases (such as rheumatoid arthritis and multiple sclerosis) or an impaired immune system (for example, by AIDS or tuberculosis) should consult their doctor before they take echinacea.
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
National Institutes of Health (NIH), National Center for Complementary and Integrative Health: General information on the use of echinacea as a dietary supplement