On the basis of the concepts connecting parkinsonian tremor with reduced amount of serotonin in the striatum and in the light of the hypothesis of an agonistic action of pizotifen in relation to serotonin a trial was undertaken to reduce parkinsonian tremor in 12 patients administering Sandomigran in daily doses of 1.5 mg. A significant reduction of tremor was achieved in two-thirds of these patients. No side effects or increased intensity of other parkinsonian signs were observed.