GradedHealth

Do feverfew and butterbur prevent migraines?

Butterbur cut migraine attacks in several small trials, and feverfew results are mixed. Butterbur also carries a rare risk of liver injury.

Published October 2026

Short answer

Butterbur extract reduced migraine attacks in small trials, but it carries a rare liver risk. Feverfew results are mixed, so its benefit is unclear. Evidence grade C (Limited). Several small placebo-controlled trials and reviews; downgraded for small size, mixed results and high risk of bias.

Key takeaways

  • In a 4-month trial of 245 adults, a butterbur extract at 75 mg twice a day cut migraine attacks by 48%, against 26% on placebo (per-protocol analysis) [1].
  • Feverfew results are mixed: a 2015 Cochrane review found only one larger, rigorous trial with a clear benefit, averaging 0.6 fewer attacks a month than placebo [2].
  • Butterbur has been linked to rare liver injury: a 2019 review of reports on one extract counted nine severe cases, two of which needed a liver transplant [3].
  • A 2020 systematic review rated butterbur's evidence as positive but limited, with high risk of bias in many studies [4].

The short version

Butterbur, a root extract of the plant Petasites hybridus, has the more positive evidence for preventing migraines. Trials of a standardised extract called Petadolex found fewer attacks than placebo, although the trials are small [1][5]. Feverfew results are mixed: the best recent trial found a modest benefit, but older trials did not [2]. Butterbur also carries a rare risk of liver injury [3].

What the studies show

For feverfew, a Cochrane review of five trials with 343 people found results that were mixed and did not convincingly show a benefit over placebo [6]. In a 147-person dose-response trial, feverfew did not beat placebo overall, and only people with at least four attacks a month at the start showed a benefit [7]. A 170-person trial of a feverfew extract at 6.25 mg three times a day found attacks fell by 1.9 a month, against 1.3 on placebo [8]. The 2015 Cochrane update adds a larger trial of 218 people that reported a difference of 0.6 attacks a month, but the review calls this low-quality evidence [2].

For butterbur, the largest trial enrolled 245 adults. Over four months, attacks fell by 48% on 75 mg twice a day, against 26% on placebo, in the per-protocol analysis [1]. A reanalysis of a 60-person trial found 45% of people on the extract had at least half as many attacks, against 15% on placebo [9]. In a trial of 58 children, butterbur was better than placebo at six-month follow-up, but not straight after the 12-week treatment [10]. A 2006 review of two trials (293 people) found moderate evidence for the higher dose of 150 mg a day, which worked better than 100 mg and placebo [5].

The nuances

Butterbur's benefit depends on the dose. In the largest trial, 50 mg twice a day was not significantly better than placebo [1]. Most butterbur trials tested the same brand, Petadolex, so the results may not carry over to other butterbur products [5][9].

The 60-person butterbur trial appears in two journals with the same design and results [11][12]. Counting it once, the butterbur evidence rests on a few small trials.

The butterbur safety reviews were written by authors with ties to the maker of Petadolex, and the maker funded some of the safety studies [3][13]. Feverfew's trials report only mild, short-lived side effects, most often stomach upset and mouth ulcers [2][6].

Safety: butterbur and the liver

Butterbur can cause liver injury, but it is rare. A 2003 review described four probable cases of reversible cholestatic hepatitis linked to long-term use, about one case in 175,000 people, and noted that modern CO2-extracted products have pyrrolizidine alkaloids below detection limits [14]. A 2019 review of spontaneous reports on Petadolex counted nine severe cases, two of which needed a liver transplant; 22 patients also reported other liver-affecting medicines, especially during painful periods [3]. A 2022 narrative review reported no relevant liver test changes in the controlled trials of Petadolex [13]. Side effects in the trials were mostly mild stomach effects, such as burping [1].

What this means for you

The studies do not show whether either herb is safe in pregnancy or for people with liver disease, so talk to a doctor first. If you take other medicines, including pain relievers, ask a pharmacist or doctor about liver risk before starting butterbur. If you notice symptoms of liver trouble while taking butterbur, stop and seek medical advice [3]. For the full picture, see the feverfew and butterbur topic page.

Go deeper

  • Feverfew and butterbur — Butterbur, a Petasites root extract sold as Petadolex, may reduce how often adults get migraines, based on several small placebo-controlled trials.

References

  1. Petasites hybridus root (butterbur) is an effective preventive treatment for migraine.. Neurology, 2004.
  2. Feverfew for preventing migraine.. Cochrane Database Syst Rev, 2015.
  3. Hepatobiliary Events in Migraine Therapy with Herbs-The Case of Petadolex, A Petasites Hybridus Extract.. J Clin Med, 2019.
  4. Herbal treatments for migraine: A systematic review of randomised-controlled studies.. Phytother Res, 2020.
  5. Effectiveness of Petasites hybridus preparations in the prophylaxis of migraine: a systematic review.. Phytomedicine, 2006.
  6. Feverfew for preventing migraine.. Cochrane Database Syst Rev, 2004.
  7. The efficacy and safety of Tanacetum parthenium (feverfew) in migraine prophylaxis--a double-blind, multicentre, randomized placebo-controlled dose-response study.. Cephalalgia, 2002.
  8. Efficacy and safety of 6.25 mg t.i.d. feverfew CO2-extract (MIG-99) in migraine prevention--a randomized, double-blind, multicentre, placebo-controlled study.. Cephalalgia, 2005.
  9. The first placebo-controlled trial of a special butterbur root extract for the prevention of migraine: reanalysis of efficacy criteria.. Eur Neurol, 2004.
  10. Butterbur root extract and music therapy in the prevention of childhood migraine: an explorative study.. Eur J Pain, 2008.
  11. An extract of Petasites hybridus is effective in the prophylaxis of migraine.. Altern Med Rev, 2001.
  12. An extract of Petasites hybridus is effective in the prophylaxis of migraine.. Int J Clin Pharmacol Ther, 2000.
  13. Petasites for Migraine Prevention: New Data on Mode of Action, Pharmacology and Safety. A Narrative Review.. Front Neurol, 2022.
  14. [The common butterbur (Petasites hybridus)--portrait of a medicinal herb].. Forsch Komplementarmed Klass Naturheilkd, 2003.