Involvement of the sympathetic nervous system in the pathogenesis of migraine attack has long been hypothesized, on the basis of anatomical, clinical and biochemical data.A double-blind placebo-controlled randomized study was carried out on 2 groups of 20 patients each: the first was affected by common migraine, the second by tension headache. Clonidine and mianserine effects were evaluated by testing the threshold of histamine-induced migraine, the intensity of induced pain and the migraine attacks' characteristics, after 90 days' preventive treatment. Hamilton Rating Scale for Depression was administered to evaluate anxiety and depression during the treatment. A long-term preventive effect on migraine incidence was registered using both drugs.