Feverfew for preventing migraine.

BACKGROUND: Feverfew (Tanacetum parthenium L.) is a popular herbal remedy for migraine. OBJECTIVES: To systematically review the evidence for or against the efficacy of feverfew versus placebo for the prevention of migraine. SEARCH STRATEGY: Electronic literature searches were performed using the databases CISCOM (Research Council for Complementary Medicine, London, UK), MEDLINE, EMBASE, Biosis and the Cochrane Library (each from its inception to April 1998). Manufacturers were contacted and the bibliographies of identified articles checked for further trials. SELECTION CRITERIA: Randomised, placebo-controlled, double-blind trials assessing the efficacy of feverfew for preventing migraine were included. No restrictions regarding the language of publication were imposed. DATA COLLECTION AND ANALYSIS: Data on patients, interventions, methods, outcomes and results were extracted in a pre-defined, standardised manner. Methodological quality was evaluated using the scoring system developed by Jadad and colleagues. Both data extraction and the assessment of methodological quality were performed independently by two reviewers. MAIN RESULTS: Four trials met the inclusion criteria. The majority of these trials suggested beneficial effects of feverfew compared with placebo. However, the trial with the highest methodological quality, which was also among the largest, found no significant difference between feverfew and placebo. REVIEWER'S CONCLUSIONS: The efficacy of feverfew for the prevention of migraine has not been established beyond reasonable doubt.