A woman with atopy experienced anaphylaxis after taking, among other dietary 
supplements, a commercial extract of echinacea. Hypersensitivity was confirmed 
by skinprick and RAST testing. Regular ingestion of echinacea by up to 5% of 
surveyed patients with atopy, combined with detection of echinacea-binding IgE 
in atopic subjects (19% by skin testing; 20% with moderate to strong reactivity 
by RAST testing), raises the possibility of severe allergic reactions, even with 
first-time use, due to cross-reactivity with other structurally similar 
allergens. Patients with atopy should be cautioned about the risk of developing 
life-threatening reactions to complementary medicines, including echinacea.