Butterbur (Petasites hybridus) is a shrub that grows in Europe and parts of Asia and North America. It is promoted as a supplement mainly to prevent migraines and for allergic rhinitis (hay fever).
Also known as: Petasites hybridus, petasites.
A 4-month migraine trial compared 50 mg and 75 mg of a butterbur root extract twice a day with placebo (Lipton 2004). These are study protocols, not a recommendation.
It is sold in the US as a dietary supplement. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling.
What studies show: NCCIH says a butterbur root extract may reduce how often migraines happen in adults and children, and a leaf extract may help hay fever symptoms. In a trial of 245 people with migraine, 75 mg twice a day for 4 months cut attacks by 48%, versus 26% on placebo; 50 mg twice a day was not clearly better than placebo (Lipton 2004). The American Academy of Neurology recommended butterbur for migraine prevention in 2012 but stopped in 2015 because of serious safety concerns (NCCIH).
Safety, per NCCIH: the butterbur plant contains pyrrolizidine alkaloids (PAs), which can damage the liver and lungs and may cause cancer. Only products processed to remove PAs and labeled or certified PA-free should be considered. PA-free products seem safe by mouth for up to 16 weeks, but there have been rare cases of liver injury with products reported to be PA-free. Side effects include burping, diarrhea, drowsiness, rash and stomach upset. People allergic to ragweed, chrysanthemums, marigolds or daisies may react to it. Products with PAs should not be used in pregnancy or breastfeeding, and little is known about PA-free products then.
We could not find a single published half-life or time to peak for butterbur that applies to a supplement dose, so we do not list one. Plant and bee products are mixtures of many compounds, so no single figure would describe them.
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