Caution: Due to reports of liver toxicity, butterbur products are being voluntarily withdrawn from markets in the United Kingdom. Based on these reports, butterbur should not be used unless a doctor determines that the potential benefits outweigh the risks. People taking butterbur should be monitored by the doctor for adverse effects.
Botanical names:
Petasites frigidus, Petasites hybridus

Parts Used & Where Grown

Butterbur, or Petasites hydridus, is found in colder, northern regions of Russia and Europe. A species native to the northern United States and much of Canada is Petasites frigidus. All parts of either plant are used, including root, rhizome, leaves, and flowers. Both species are easily confused with their close cousin, Eastern coltsfoot (Tussilago farfara), a plant that looks the same and has similar properties and hazards.

What Are Star Ratings?

This supplement has been used in connection with the following health conditions:

Used forWhy
3 Stars
Hay Fever
1 tablet standardized to contain 8 mg petasin extract two to three times a day for two weeks
Studies have shown butterbur extract to be effective at reducing hay fever symptoms.

Two double-blind studies have compared extract to standard antihistamine drugs in people with hay fever. The first compared it with the drug cetirizine (Zyrtec) and found the drug and butterbur extract relieved symptoms equally well. However, cetirizine caused significantly more adverse effects, including a high rate of drowsiness. The second study compared butterbur extract with fexofenadine (Allegra) and placebo. Butterbur extract was as effective as fexofenadine at relieving symptoms, and both were significantly better than placebo.

People with hay fever had better symptomatic relief and reductions in levels of immune cells associated with allergic reactions (eosinophils) when treated with an herbal formula containing horny goat weed compared with a formula without horny goat weed and another herb by itself. Traditionally 5 grams (1 tsp) of horny goat weed is taken three times per day, usually after being simmered (decocted) in 250 ml (1 pint) of water for 10 to 15 minutes.

In a double-blind study, an extract of the butterbur plant (Petasites hybridus) was significantly more effective than a placebo at improving symptoms in people suffering from seasonal allergic rhinitis. The study used a preparation standardized to contain 8 mg of total petasin per tablet. One tablet was administered either two or three times a day for two weeks; the larger amount was found to be more effective than the smaller amount.

3 Stars
Migraine Headache
Adults: 75 mg twice a day of an extract standardized to contain at least 15% petasins; children: reduce amount according to body weight
Butterbur extract has been shown to significantly reduce the frequency of migraine attacks.

Double-blind trials have demonstrated that extract can reduce the frequency of migraine attacks significantly better than placebo. One study has also shown it helps reduce the frequency of migraine headaches in children and adolescents, though there was no control group so it is not as clear just how effective butterbur extract is in this population. In a double-blind trial, supplementing with an extract of (Petasites hybridus) for four months was significantly more effective than a placebo at reducing the frequency of migraine attacks. The amount of butterbur found to be effective was 75 mg twice a day of an extract standardized to contain at least 15% petasins. A smaller amount (50 mg twice a day) was ineffective. The most common side effect was burping.

2 Stars
Adults: 50 mg three times per day for adults; children: 50 to150 mg per day, depending on body size
In one study, asthma patients taking inhaled steroids who also took butterbur extract saw significant improvement in airflow.

In a double-blind study, adult asthma patients taking inhaled steroids took either extract or placebo. There was a significantly greater improvement in airflow in the group that took butterbur extract compared with those who took placebo. A study without a control group showed that people with mild asthma, most still taking various anti-asthma medications, had better airflow but actually showed some evidence of having more frequent asthma attacks when they took butterbur. Therefore more rigorous studies are needed to know how effective butterbur is in people with asthma.

Traditional Use (May Not Be Supported by Scientific Studies)

Traditionally the entire plant was used as a demulcent to soothe a dry, spasmodic cough.1 It was primarily made into a tea, and used only for short periods of time. Using the herb as a tea may have helped reduce the liver’s exposure to butterbur's toxic compounds, as they are not normally water soluble.

How It Works

Botanical names:
Petasites frigidus, Petasites hybridus

How It Works

Butterbur contains petasins, a group of bitter-tasting compounds in a class of chemicals called sesquiterpenoids. Petasine is a specific petasin considered important in butterbur. Petasins relax blood vessels and various smooth muscles in the body, such as those that are found in the uterus and lungs, according to test tube and animal studies.2 Petasins are also known to reduce inflammation, as demonstrated in human studies.3 Because of these properties, butterbur might be expected to be beneficial for people with migraines and asthma. Butterbur extracts have consistently been shown to reduce symptoms in people with migraines more effectively than placebo. Butterbur has also been shown to help people with asthma, although the results have been conflicting.4, 5, 6 Some studies have also shown that butterbur extract works just as well as a common antihistamine drug for people with hay fever, but without causing drowsiness.

Butterbur also contains unsaturated pyrrolizidine alkaloids. These can cause severe liver damage in some people if taken for too long. Only extracts that exclude pyrrolizidine alkaloids should be used.

How to Use It

The most commonly available product is an extract of the rhizome of Petasites hybridus standardized to contain 7.5 mg of petasine per capsule. This type of extract removes the pyrrolizidine alkaloids to avoid causing liver damage. Intake is usually 1 to 2 capsules three times per day.


Botanical names:
Petasites frigidus, Petasites hybridus

Interactions with Supplements, Foods, & Other Compounds

At the time of writing, there were no well-known supplement or food interactions with this supplement.

Interactions with Medicines

As of the last update, we found no reported interactions between this supplement and medicines. It is possible that unknown interactions exist. If you take medication, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.

Side Effects

Botanical names:
Petasites frigidus, Petasites hybridus

Side Effects

There are no known side effects as long as pyrrolizidine alkaloids are not present. When they are present, they can cause serious liver damage and even liver failure or death. Therefore, pyrrolizidine alkaloid–containing extracts should not be used.


1. Moore M. Medicinal Plants of the Pacific West. Santa Fe NM: Red Crane Books, 1993.

2. Wang GJ, Shum AY, Lin YL, et al. Calcium channel blockade in vascular smooth muscle cells: Major hypotensive mechanism of S-petasin, a hypotensive sesquiterpene from Petasites formosanus. J Pharmacol Exp Ther 2001;297:240-6.

3. Thomet OA, Schapowal A, Heinisch IV, et al. Anti-inflammatory activity of an extract of Petasites hybridus in allergic rhinitis. Int Immunopharmacol 2002;2:997-1006.

4. Lipton RB, Gobel H, Einhaupl KM, et al. Petasites hybridus root (butterbur) is an effective preventive treatment for migraine. Neurology 2004;63:2240-4.

5. REF:Lee DK, Haggart K, Robb FM, Lipworth BJ. Butterbur, a herbal remedy, confers complementary anti-inflammatory activity in asthmatic patients receiving inhaled corticosteroids. Clin Exp Allergy 2004; 34:110-4.

6. Ziolo G, Samochewiec L. Study on clinical properties and mechanism of action of petasites in bronchial asthma and chronic obstructive bronchitis. Pharm Acta Helv 1998;72:378-80.

This information does not replace the advice of a doctor. Healthwise, Incorporated, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Learn how we develop our content.