An overview of the literature on calcium channel blockers in the treatment of patients with tardive dyskinesia is followed by a presentation of preliminary results of the authors own pilot study on the efficacy of Diltiazem treatment in an open sample of 11 schizophrenic patients with dyskinesic symptoms. Diltiazem was administered in the daily dose of 60 mg for 6 weeks. In the group under study more marked symptom relief was noted in patients with severe dyskinesic disorders of relatively recent onset. Symptom relief was noted, above all, as regards acathisia and involuntary movements of the lower limbs, after a relatively long (continued for 5 to 6 weeks) treatment with Diltiazem. No serious side effects were found. In some patients the subsidence of tardive dyskinesias was associated with an amelioration of their mental state.