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.)
Claims for Echinacea
People take echinacea mostly to help prevent or treat viral infections in the upper respiratory tract, such as the common cold. Some people apply echinacea as a cream or ointment to treat skin disorders and promote healing of wounds. Proponents claim that echinacea has antioxidant and anti-inflammatory effects, helping to prevent cancer and other diseases. Antioxidants protect cells against damage by free radicals, which are highly chemically active by-products of normal cell activity.
Evidence for Echinacea
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 the supplement's ingredients.
Some preliminary evidence shows that taking echinacea may help decrease some of the inflammatory molecules (cytokines) that are involved in COVID-19 infection and may help diminish occurrence of acute respiratory distress syndrome (ARDS) that occurs in some people. However, this has not been substantiated.
No rigorous scientific studies support claims that echinacea helps prevent cancer or improves immunity, blood sugar, anxiety, and inflammation, or promotes wound healing.
Side Effects of Echinacea
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.
Drug Interactions with Echinacea
Echinacea taken for longer than 8 weeks may interact with medications 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. Echinacea
Recommendations for Echinacea
Echinacea is probably safe for short-term use, but whether it helps boost the immune system and prevents viral infections, such as the common cold, is unknown. People who have autoimmune diseases (such as rheumatoid arthritis and multiple sclerosis), have received organ transplants, or have an impaired immune system (for example, by AIDS or tuberculosis) should consult their doctor before they take echinacea.
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
National Institutes of Health's National Center for Complementary and Integrative Health: Echinacea
