There have been a few studies of butterbur for migraines and allergic rhinitis (hay fever) in people, so we have some knowledge of its effects on these two conditions.

Butterbur appears to help reduce the frequency of migraines in adults and children. In 2012, the American Academy of Neurology recommended its use for preventing migraines. However, the Academy stopped recommending it in 2015 because of serious concerns about possible liver toxicity.

Some studies of the root or leaf extracts suggest that they may be helpful for symptoms of hay fever (allergic rhinitis), but the data is not convincing.

One study suggested that a combination product containing butterbur might improve anxiety and depression in people with somatoform disorders. (Somatoform disorders are characterized by physical complaints for which no physiological explanation is found and for which psychological factors are likely involved.)

Butterbur has not been proven helpful for allergic skin reactions, chronic obstructive bronchitis, insomnia, upset stomach, urinary tract symptoms, asthma, and other conditions.

Side Effects Of Butterbur

Some butterbur products contain chemicals called pyrrolizidine alkaloids (PAs). PAs can damage the liver, lungs, and blood circulation, and possibly cause cancer. Only products that have been processed to remove PAs and are labeled or certified as PA-free should be considered for use.

Some countries have withdrawn butterbur products from the market because of concerns about liver toxicity.

Some experts recommend that it not be used for treating migraine because of its safety concerns.

Not enough is known about whether it’s safe to apply butterbur products to the skin.

Several studies, including a few studies of children and adolescents, have reported that PA-free butterbur products seem to be safe when taken by mouth in recommended doses for up to 16 weeks. However, some products claiming to be PA-free may not in fact be. For example, Petadolex is marketed as a PA-free butterbur product, but it has been associated with liver damage in some people, suggesting that it may have had PAs. Also, the safety of longer-term use has not been established.

Butterbur products with PAs should not be used during pregnancy or while breastfeeding because they may cause birth defects or liver damage. Little is known about whether it’s safe to use PA-free butterbur during pregnancy or while breastfeeding.

PA-free butterbur is generally well tolerated but can cause side effects such as belching, headache, itchy eyes, diarrhea, breathing difficulties, fatigue, upset stomach, and drowsiness.

Butterbur may cause allergic reactions in people who are sensitive to plants such as ragweed, chrysanthemums, marigolds, and daisies.

If you’re planning to use butterbur or to give it to your child, tell your (or the child’s) health care provider. Health care providers may consider liver function monitoring for people using it.


Take charge of your health—talk with your health care providers about any complementary health approaches you use. Together, you can make shared, well-informed decisions.


All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.