The effects of haloperidol in the management of elderly patients with chronic brain syndrome with cerebral arteriosclerosis or senile brain disease were investigated in an initial open phase (6 patients) and a subsequent randomized double-blind placebo-controlled phase (18 patients). Haloperidol appears to be an effective compound in patients who are agitated, overactive and hostile. Side effects include sedation and extrapyramidal symptoms. The dose level should be considerably lower than that generally used in schizophrenic patients and should probably not exceed 4 mg. daily. Maintenance doses of about 1 mg. daily appear adequate in most cases. Hypotension was not a complication and no untoward effects on liver function or bone marrow were noted.