Research published in Headache (2005; 45(3): 196-203) looked at the effect butterbur root extract had on children and adolescents suffering from migraine headaches. The subjects of the study were between the ages of six and 17, with a history of migraine headaches dating back at least one year. Butterbur extract was given (50-150 mg/day–depending on the weight of the subject) daily for four months. Symptoms were recorded in a journal and 77% of those supplemented with butterbur had a reduction in the number of migraine episodes by at least 50%–with 91% of the subjects reporting that they had experienced improvement of their symptoms.
A double-blind, placebo-controlled study appearing in The Lancet (July 23, 1998;189-192) found that treatment with a feverfew extract reduced the frequency and severity of migraine attacks. The study lasted four months and data was available on 59 patients.