What Is Butterbur?

Learn more about this herbal remedy for migraines and allergies

Butterbur (Petasites hybridus) is a shrub that grows in the northern parts of Europe and Russia. It has been used since at least the 17th century to treat a range of medical conditions, including wounds, coughs, and asthma. Today, butterbur is best known as a treatment for migraines and allergic rhinitis (hay fever).

This article looks at the scientific research into butterbur's use as a treatment for migraines and hay fever. It also discusses dosage, safety, and what to look for when buying butterbur.

Butterbur plant close up
Jurgen Wiesler / imageBROKER / Getty Images 

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement that has been tested by a trusted third party, such as USP, ConsumerLabs, or NSF. However, even if supplements are third-party tested, that doesn’t mean that they are necessarily safe for all or effective in general. It is important to talk to your healthcare provider about any supplements you plan to take and to check in about any potential interactions with other supplements or medications.

  • Active ingredients: Petasin, isopetasin
  • Alternate names: Blatterdock, bog rhubarb, bogshorns, butter-dock, pestwurz
  • Legal status: Butterbur can be purchased over the counter in the United States
  • Suggested dose: 100 to 150 mg per day in two or three divided doses
  • Safety considerations: Fresh butterbur contains pyrrolizidine alkaloids (PAs), which can be harmful to your liver. Make sure to buy butterbur that is certified PA-free.

Uses of Butterbur

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, herbalist, or doctor. No supplement is intended to treat, cure, or prevent disease. 

Butterbur gets its name from a time when people would wrap butter in its huge leaves to prevent melting. Today, people use butterbur to address a myriad of health complaints, including:

Of these, there has been more scientific research to support its use as a treatment for migraines and hay fever. However, the National Center for Biotechnical Information cautions that "its long-term efficacy and safety have not been established, and it is not specifically approved for these uses in the United States."


In 2012, the American Headache Society (AHS) and the American Academy of Neurology (AAN) endorsed the use of a butterbur extract to reduce the frequency of migraines. They made this recommendation based on two high-quality studies involving an extract called Petadolex, which is made from butterbur root.

The exact way butterbur works is unknown. It's thought that an active component of butterbur called petasin may have anti-inflammatory and other effects. For instance, it may relax blood vessels in the brain that become overexcited during a migraine.

Regardless of the mechanism, a number of studies have concluded that a Petadolex dose of up to 150 milligrams twice daily, taken for up to three to four months, reduced the frequency of migraines compared to placebo. These studies also found no significant adverse effects.

Allergic Rhinitis (Hay Fever)

Traditionally, butterbur has been used to treat asthma and bronchitis and reduce mucus. Some studies have concluded that butterbur extracts may be as effective as second-generation antihistamines. The results aren't always consistent for all patients, however.

Butterbur is thought to work in a similar way to allergy medications: by blocking the action of histamine and leukotrienes. These are inflammatory chemicals involved in allergic reactions.

In an older study of 330 people, a butterbur extract was compared with the antihistamine drug Allegra (fexofenadine) and a placebo. Butterbur was as effective as Allegra at relieving sneezing, nasal congestion, itchy eyes, and other hay fever symptoms. And both treatments were more effective than the placebo.

And finally, a study of 125 people with hay fever found butterbur extract to be as effective as Zyrtec (cetirizine). It's worth noting that some of the larger trials were sponsored by manufacturers of butterbur extract and at least one double-blind, placebo-controlled study with negative results was published in 2004.

What Are the Side Effects of Butterbur?

Several studies, including a few of children and adolescents, have reported that PA-free butterbur products are safe and well tolerated. These studies have focused on recommended doses taken by mouth for up to 16 weeks. The safety of longer-term use has not been established.

Butterbur is usually well tolerated, but it can cause side effects such as:

  • Belching
  • Headache
  • Itchy eyes
  • Diarrhea
  • Breathing difficulties
  • Fatigue
  • Drowsiness


Raw (unprocessed) butterbur contains chemicals called pyrrolizidine alkaloids (PAs). These can cause liver damage and have been shown to be carcinogenic in animal studies. These substances are typically removed in commercially available preparations.

Make sure any butterbur products you use are certified and labeled “PA‐free.”

Butterbur is a member of the ragweed plant family. This means people who are allergic to ragweed, marigolds, daisies, or chrysanthemums should avoid butterbur.

People who are pregnant, plan to become pregnant, or who are nursing should also not take butterbur. This is because not enough is known about its potential effects. Similarly, people with liver disease or liver dysfunction should avoid butterbur because some the compounds could damage the liver.

Dosage: How Much Butterbur Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs. 

The typical oral dosage for an adult is between 100 and 150 milligrams (mg) per day in two or three divided doses. Children should not take more than 50–75 mg twice daily.

What Happens If I Take Too Much Butterbur?

There are no reports of overdose when taking PA-free butterbur. However, you should follow the manufacturer's dosage recommendations.


Avoid taking butterbur if you are taking anticholinergics or CYP3A4 inducers.

It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included. Please review the supplement label with your healthcare provider to discuss any potential interactions with foods, other supplements, and medications.

How to Store Butterbur

Keep butterbur supplements in their original packaging in a cool, dry place.

Similar Supplements

Feverfew has also been studied for its efficacy in preventing migraine headaches. There is no clear evidence yet to support its use for this purpose.

Butterbur and feverfew are sometimes sold as a combination supplement and are likely safe to take at the same time.

Frequently Asked Questions

  • Does butterbur cause liver damage?

    Unprocessed butterbur contains chemicals called pyrrolizidine alkaloids (PAs), which can cause liver damage. It is believed safe to take butterbur supplements that are certified PA-free.

  • Is butterbur safe to take daily?

    Long-term use of butterbur has not been well studied. Research suggests that it is probably safe to use butterbur daily for up to four months.

Sources of Butterbur & What To Look For

Butterbur is sold in a variety of formulations, including:

  • Capsules
  • Softgels
  • Powders
  • Tinctures
  • Teas

There are a number of patented extract forms of butterbur, including Petadolex. Petadolex contains no less than 15% petasins. The same formulation has been used in many migraine trials.

Again, only those products labeled or certified as PA-free should be used to avoid the potentially harmful chemicals found naturally in the butterbur plant but removed during processing.


Butterbur is a shrub that's used to prevent migraine headaches and treat hay fever. There is some evidence to support its use for this purpose, but more research is needed.

Butterbur is generally considered safe as long as it is PA-free. Never take unprocessed butterbur, as it can cause liver damage.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Center for Complementary and Integrative Health. Butterbur.

  2. National Center for Biotechnical Information. Butterbur.

  3. Silberstein SD, Holland S, Freitag F, et al. Evidence-based guideline update: Pharmacologic treatment for episodic migraine prevention in adults: Report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Headache SocietyNeurology. 2012;78(17):1337–1345. doi:10.1212/WNL.0b013e3182535d20.

  4. Prieto JM. Update on the efficacy and safety of Petadolex®, a butterbur extract for migraine prophylaxis. Bot Targets Ther. 2014;4:1-9. doi:10.2147/BTAT.S54023

  5. Lewis SJ, Keister DM. Is butterbur an effective treatment for allergic rhinitis? Evid Based Pract. 2017;20(11):15. doi:10.1097/01.EBP.0000541879.42327.4f

  6. Hoang MP, Chitsuthipakorn W, Snidvongs K. Herbal medicines for allergic rhinitis: a systematic review and meta-analysis. Curr Allergy Asthma Rep. 2021;21(4):1-2. doi:10.1007/s11882-021-00999-9

  7. Diener H, Freitag F, Danesch U. Safety profile of a special butterbur extract from Petasites hybridus in migraine prevention with emphasis on the liverCephalalgia Reports. 2018;1:251581631875930. doi:10.1177/2515816318759304.

  8. Memorial Sloan Kettering Cancer Center. Butterbur.

  9. Misra SM, Kaplan RJ, Verissimo AM. Modalities of complementary and alternative medicine. In: Giardino AP, ed. A Guide to Integrative Pediatrics for the Healthcare Professional. Houston, TX: Springer; 2014.

  10. Grazzi L, Toppo C, D’Amico D, et al. Non-pharmacological approaches to headaches: non-invasive neuromodulation, nutraceuticals, and behavioral approaches. Int J Environ Res Public Health. 2021;18(4):1503. doi:10.3390/ijerph18041503

Additional Reading

By Colleen Doherty, MD
 Colleen Doherty, MD, is a board-certified internist living with multiple sclerosis.