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.

Researchers documented one case of anaphylaxis from echinacea and confirmed the allergic response through skin prick and blood (RAST) testing. They also surveyed patients with atopic conditions to measure how many used echinacea and tested positive for echinacea-specific antibodies.

Funding not disclosed in abstract