Butterbur: The plants commonly referred to as Butterbur are found in the daisy family Asteraceae in the genus Petasites, species P. vulgaris or P. hybridus. The plants are found in the temperate zone of the Northern Hemisphere and prefer moist environments such as riverbanks and marshes. The rhizome (root) of the plant has been used as an herbal remedy for fever, asthma, colds, and urinary complaints and was also thought to be a cardiac "tonic" and a diuretic.
Commercial preparations include Petadolex (available in the United States since 1997), Tesalin, and Petaforce. A few small clinical trials have shown some benefit in the treatment of migraines and allergic rhinitis.