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7 peer-reviewed studies
What the evidence says
Most Butterbur studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 2002–2024 with a typical study size of 131 participants.
Based on 7 studies · 1 meta-analysis · 3 RCTs · 437 total participants
Confidence
ModerateBy outcome
1 study in the last 5 years · Latest meta-analysis: 2024
A 3-arm RCT (n=245) found Petasites extract 75mg twice daily reduced migraine attack frequency by 48% vs 26% for placebo (p=0.0012); the 50mg dose was not significantly better than placebo.
Lipton RB et al. · Neurology (2004)
A systematic review concluded Petasites hybridus preparations are effective for migraine prophylaxis.
Agosti R et al. · Phytomedicine : international journal of phytotherapy and phytopharmacology (2006)
A randomized BMJ trial found butterbur as effective as cetirizine for seasonal allergic rhinitis, without the sedation.
Schapowal A et al. · BMJ (Clinical research ed.) (2002)
A systematic review and meta-analysis of medicinal plants for allergic rhinitis included butterbur among effective options.
Lim XY et al. · PloS one (2024)
A systematic review of herbal migraine treatments found butterbur among those with supportive randomized evidence.
Lopresti AL et al. · Phytotherapy research : PTR (2020)
A randomized, double-blind trial found butterbur extract Ze339 had dose-dependent efficacy for intermittent allergic rhinitis.
Schapowal A et al. · Archives of otolaryngology--head & neck surgery (2004)
An evidence-based systematic review summarized butterbur's uses and flagged the pyrrolizidine-alkaloid hepatotoxicity concern.
Giles M et al. · Journal of herbal pharmacotherapy (2005)