A double-blind, placebo-controlled study published in Cephalalgia (2005; 25(11): 1031–1041) examined the effects of the herb feverfew on migraine headaches. The study included 170 patients with migraine, who were randomly assigned to receive either a placebo or 6.25 mg of feverfew three times per day.

Before treatment began, the average number of migraine headaches per 28-day period was recorded for both groups. After the treatment phase, headache frequency was assessed again. Patients receiving feverfew experienced a greater reduction in the number of migraines compared to the placebo group.