d a carbon dioxide extract of petasites, with 8.0 mg total petasine per tablets. The dose was one tablet four times daily. The participants on antihistamines were given a single 10 mg tablet daily.
While the butterbur recipients did not report any adverse symptoms, a small number of people taking antihistamines reported side effects, mostly drowsiness and fatigue. Dr Schapowal states that the group has no data on whether butterbur works as an ongoing treatment, but treatment for allergy sufferers is often restricted to peak periods.