The first placebo-controlled trial of a special butterbur root extract for the prevention of migraine: reanalysis of efficacy criteria

Eur Neurol. 2004;51(2):89-97. doi: 10.1159/000076535. Epub 2004 Jan 28.


This is an independent reanalysis of a randomised, placebo-controlled parallel-group study on the efficacy and tolerability of a special butterbur root extract (Petadolex) for the prophylaxis of migraine. The original protocol and analysis had a number of major shortcomings. In order to follow regulatory requirements, an independent reanalysis of the original data was performed. Following a 4-week baseline phase, 33 patients were randomised to treatment with two capsules 25 mg butterbur twice a day and 27 to placebo. The mean attack frequency per month decreased from 3.4 at baseline to 1.8 after 3 months (p = 0.0024) in the verum group and from 2.9 to 2.6 in the placebo group (n.s.). The responder rate (improvement of migraine frequency > or =50%) was 45% in the verum group and 15% in the placebo group. Butterbur was well tolerated. This small trial indicates that butterbur may be effective in the prophylaxis of migraine.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Case-Control Studies
  • Double-Blind Method
  • Drug Administration Schedule
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Migraine Disorders / prevention & control*
  • Petasites / chemistry*
  • Phytotherapy*
  • Plant Preparations / therapeutic use*
  • Prospective Studies
  • Statistics, Nonparametric
  • Treatment Outcome


  • Plant Preparations