thumb|Butterbur in [[Ystad.]]
Petasites hybridus, also known as the butterbur, is a herbaceous perennial flowering plant in the family Asteraceae that is native to Europe and northern Asia. Concerns about the potential toxic effects of pyrrolizidine alkaloids in butterbur limit its use in human and animal studies.
Common names
Butterbur may have derived from the use of leaves to wrap butter centuries ago.
The flowers are produced in the early spring, before the leaves appear. They are pale pink, with several inflorescences clustered on a stem. The leaves are large, on stout tall stems, round, with a diameter of with petioles up to .
Distribution
It is native to central Europe, extending from the British Isles to the Caucasus, and from southern Italy to southern Scandinavia. It is present as an introduced species in North America.
Dietary supplement and research
As there are no approved clinical uses of butterbur or its extracts, preparations are sold in some countries as a dietary supplement.
Traditional medicine
Petasites hybridus leaves were used in Austrian and Czech traditional medicine internally (as tea or cold maceration in ethanol) and externally (as compresses or maceration in vinegar) for treatment of infections, fever, flu, colds, hay-fever, and allergies.
Phytochemicals
Petasites hybridus contains senecionine and other toxic pyrrolizidine alkaloids in its leaves and roots.
Long-term health effects and interaction of butterbur with other drugs have not been well documented. However, it can theoretically interact with certain blood pressure and heart medications, as well as with drugs that can induce a liver enzyme called CYP3A4.