Merck Manual

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Laura Shane-McWhorter

, PharmD, University of Utah College of Pharmacy

Last full review/revision Jul 2020| Content last modified Jul 2020
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Echinacea is a perennial wildflower containing a variety of biologically active substances. Various parts of the plant are used medicinally.

Medicinal claims

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.

Possible side effects

No dangerous side effects have been identified, but some people experience dizziness, fatigue, headache, and digestive upset. People with allergies to certain plants (for example, ragweed, chrysanthemum, marigold, daisies) may have allergic reactions when they take echinacea.

Possible drug interactions

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.

More Information about 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.

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