Butterbur
Petasites hybridus
A marshland herb with strong evidence for migraine prevention and allergic rhinitis. Crucially, only PA-free (pyrrolizidine-alkaloid-free) certified products should ever be used because raw butterbur is liver-toxic.
What is Butterbur?
Butterbur (Petasites hybridus) is a perennial shrub found in wet, marshy ground across Europe, Asia, and North America, historically named for the use of its large leaves to wrap butter. Root and leaf extracts have a long medicinal history, and modern standardized, PA-free preparations are among the better-evidenced botanicals for both migraine prevention and seasonal allergies.
Known Health Benefits
How It Works
Butterbur's active sesquiterpenes, petasin and isopetasin, inhibit the synthesis of leukotrienes and other inflammatory mediators and exert calcium-channel-blocking, antispasmodic effects on smooth muscle. In migraine, these actions are thought to stabilize cerebral blood vessels and reduce neurogenic inflammation. In allergic rhinitis, leukotriene inhibition reduces nasal inflammation and congestion, producing antihistamine-like relief without sedation. The naturally occurring pyrrolizidine alkaloids (PAs) in the raw plant are unrelated to these benefits and must be removed during manufacturing.
What Research Says
Butterbur has notably strong trial support. A randomized controlled trial by Lipton et al. (Neurology, 2004) found that Petadolex 75 mg twice daily reduced migraine frequency by about 48% versus 26% for placebo. On the strength of such data, the American Academy of Neurology previously rated butterbur 'Level A' (effective) for migraine prevention — though it later revised guidance over hepatotoxicity concerns with non-purified products. For allergic rhinitis, several trials found butterbur comparable to antihistamines like cetirizine and fexofenadine, without the drowsiness.
Active Compounds
Petasin, isopetasin (must be PA-free of toxic pyrrolizidine alkaloids)
Forms & Bioavailability
Petasin and isopetasin are absorbed orally and standardized extracts deliver consistent amounts. The single most important quality consideration is certification that the product is PA-free; bioavailability is irrelevant if the product carries liver-toxic alkaloids.
Dosage Guidance
| Use Case | Dosage |
|---|---|
| Migraine prevention | 75 mg PA-free extract twice daily |
| Allergic rhinitis | 50 mg PA-free extract 2–3 times daily |
Always consult a healthcare provider for personalized dosing.
Potential Side Effects
PA-free extracts are generally well tolerated; most common side effect is burping. Raw or non-certified butterbur contains pyrrolizidine alkaloids that are hepatotoxic and potentially carcinogenic.
Who Should Avoid It
- Liver disease (and never use non-PA-free products)
- Pregnancy and breastfeeding
- Allergy to ragweed, marigold, daisy, or chrysanthemum (Asteraceae)
- Children, except under specialist supervision
Pregnancy & Lactation
Not recommended during pregnancy or breastfeeding due to insufficient safety data and the pyrrolizidine-alkaloid risk inherent to the plant.
Known Drug Interactions
May add to the effects of anticholinergic drugs. Because of liver concerns, use caution alongside other hepatotoxic medications. Cross-reactivity in people allergic to ragweed family plants.
Evidence Classification
Supported by cohort studies, case-control studies, or multiple observational studies with consistent findings.
Frequently Asked Questions
Is butterbur safe?
Only certified PA-free (pyrrolizidine-alkaloid-free) butterbur extracts should ever be used. The raw plant contains compounds that can damage the liver and may be carcinogenic. Choosing a reputable, PA-free standardized product is essential, and periodic liver monitoring is sometimes advised.
Does butterbur work for allergies?
Yes. Several randomized trials found PA-free butterbur as effective as some antihistamines for seasonal allergic rhinitis, with the advantage of not causing drowsiness. It works by inhibiting leukotrienes and other inflammatory mediators.
How does butterbur compare to feverfew for migraines?
Butterbur generally has stronger and more consistent trial evidence for migraine prevention than feverfew, but it carries the important PA-free safety caveat. Both are preventive rather than acute treatments and are often considered alongside magnesium and riboflavin.
References
- Petasites hybridus root (butterbur) is an effective preventive treatment for migraine. Lipton RB, Göbel H, Einhäupl KM, Wilks K, Mauskop A. Neurology (2004)View study
- Butterbur Ze 339 for the treatment of intermittent allergic rhinitis. Schapowal A; Petasites Study Group. Phytother Res (2005)View study
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This entry is for educational purposes only. It is not medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement regimen, especially if you take medications or have health conditions.