Not Found
Locations

Find information on medical topics, symptoms, drugs, procedures, news and more, written for the health care professional.

* This is the Professional Version. *

Echinacea

By Melissa G. Marko, PhD, University of the Sciences ; Ara DerMarderosian, PhD, University of the Sciences in Philadelphia

Click here for
Patient Education

Echinacea, a North American wildflower, contains a variety of biologically active substances.

Claims

Echinacea is said to stimulate the immune system. When taken at the start of a cold, it is said to shorten the duration of cold symptoms. Well-designed studies have not supported this effect.

Topical preparations are used to promote wound healing.

Evidence

Studies of echinacea's role in preventing and/or treating the common cold are inconsistent. The largest factor contributing to inconsistency is the variability of plant preparations (including different plant parts and species) and ultimately composition of the supplement. According to a 2006 Cochrane review, the aerial parts of the plant might be effective for the early treatment of colds; also, the other preparations of echinacea, might have a role in prevention of colds (1). However, more meticulous randomized, controlled trials are necessary.

Adverse effects

Most adverse effects are mild and transitory; they include dizziness, fatigue, headache, and GI symptoms. No other adverse effects are known. Theoretically, echinacea is contraindicated in patients with autoimmune disorders, multiple sclerosis, AIDS, tuberculosis, and organ transplants because it may stimulate T cells. Echinacea inhibits some cytochrome P-450 enzymes and stimulates others; it can therefore potentially interact with drugs metabolized by the same enzymes (eg, anabolic steroids, azole antifungals, methotrexate). Allergic reactions are possible in patients with allergies to ragweed, chrysanthemum, marigold, daisies, or related allergens.

Drug interactions

Echinacea inhibits some cytochrome P-450 enzymes and stimulates others; it can therefore potentially interact with drugs metabolized by the same enzymes (eg, anabolic steroids, azole antifungals, methotrexate, etoposide, and other chemotherapeutic drugs).

Echinacea reference

Drugs Mentioned In This Article

  • Drug Name
    Select Trade
  • ETOPOPHOS
  • OTREXUP

* This is the Professional Version. *