Uses: Oral echinacea is possibly effective for preventing the common cold but does not help treat colds. Various forms of echinacea may reduce the risk of developing a cold by 10% to 58% as seen in a pooled analysis of studies. But not all studies show a benefit. There is not enough evidence to say if echinacea is helpful for other conditions such as COVID-19, influenza, otitis media, and tonsillitis.

Dosing: Commonly studied doses include 300 mg three times a day for 7 to 14 days before and 5 to 7 days after an infection.

Safety: Oral echinacea is generally well-tolerated with gastrointestinal side effects and rashes being the most common adverse effects. There are reported allergic reactions, specifically in patients with atopy or allergies to ragweed or related plants being at higher risk. There have also been cases of echinacea-induced hepatitis reported.

Pregnancy: Echinacea is possibly safe when taken orally for up to 7 days in pregnancy based on limited evidence. There is insufficient evidence to determine if it is safe to use when breastfeeding.

Interactions: There are no known major interactions with echinacea. Limited data suggests that it might increase levels of drugs metabolized by CYP1A2 (ie. clozapine). It may also increase or decrease levels of drugs metabolized by CYP3A4 (ie. apixaban) but research is mixed. Patients taking immunosuppressants or those with autoimmune disorders (ie. multiple sclerosis, rheumatoid arthritis) should not use echinacea since it can stimulate immune function.

Reference: Therapeutic Research Center. Echinacea. [Natural Medicines website]. June 29, 2023. Available at: https://naturalmedicines.therapeuticresearch.com/databases/food,-herbssupplements/professional.aspx?productid=981 (Accessed October 4, 2023.) Pharmacist's Letter. November 2023, No. 391108