LiverTox: Clinical and Research Information on Drug-Induced Liver Injury

Butterbur is a popular herbal preparation that is used to treat migraine headaches, allergic rhinitis and respiratory illnesses. Butterbur is an extract of the roots of the butterbur bush and the extract has to be processed carefully to eliminate harmful pyrrolizidine alkaloids that occur naturally in the plant. Butterbur preparations processed to remove pyrrolizidine alkaloids do not appear to cause liver injury, either in the form of serum enzyme elevations during treatment or clinically apparent acute liver injury. However, recent cases of clinically apparent liver injury have been reported with use of several commercial preparations of butterbur, suspected to be due to residual pyrrolizidine alkaloid contamination.