The effectiveness of promazine hydrochloride or chlorpromazine hydrochloride in preventing psychiatric hospitalization was studied in 173 schizophrenic outpatients. Pharmacological therapy was given, with brief psychiatric interviews. The two drug groups consisted of 55 patients receiving promazine and 62 who received chlorpromazine; the comparison group of 56 patients received a placebo under double-blind conditions. The treating psychiatrist did not know which of the three substances the patients in a given group were receiving, but he was free to adjust dosage in an effort to achieve results. The two groups receiving the ataractic drugs had a significantly lower rate of subsequent hospitalization than did the group receiving the placebo. The placebo was prescribed in significantly greater amounts than the ataraxics, apparently reflecting the psychiatrist's effort to achieve results.