The migraine subject exhibits a dopaminergic vascular hypersensitivity on the brain level (CBF increase) as well as on the peripheral level (BP decrease). A dopaminergic agonist, piribedil, was administered by intravenous infusion (0,1 mg/kg over 30 minutes) to 150 patients known to suffer from migraine or other kinds of headache. 94% of migraine patients developed nausea or vomiting and 69% a decrease of BP, severe enough to discontinue the infusion. In non migraine headaches, the piribedil infusion had no effects in 61% of patients and provoked a decrease of BP in 16% of cases only. The piribedil test could be used to distinguish genuine migraine from other cephalalgia in patients prone to headache.