Echinacea-associated anaphylaxis.

Echinacea triggered a severe allergic reaction (anaphylaxis) in a woman with a history of allergies. Among people with atopic conditions, about 1 in 5 showed immune responses to echinacea in allergy testing, and up to 5% regularly used it—meaning some people could have dangerous reactions even on first use due to cross-reactivity with similar plant allergens.