title: Understanding echinacea.
mesh_terms: D002626:Chemistry, Pharmaceutical; D000075202:Contraindications; D004347:Drug Interactions; D020900:Echinacea / Q000009:adverse effects / Q000737:chemistry / Q000502:physiology; D006801:Humans; D007109:Immunity / Q000187:drug effects; D008517:Phytotherapy / Q000009:adverse effects / Q000379:methods*