Usdin and Robinson review the literature of the occurrence of psychosis during antabuse therapy and add a report of a case of their own. The clinical picture of the psychosis which was produced in their patient was that of a toxic reaction to the drug. The psychotic symptoms subsided when the does was reduced. A subsequent course of placebo treatment failed to produce the same reaction. During a second course of antabuse, the authors feel that a psychosis was averted by reducing the dose of the drug at the peak of the patient's subjective complaints. They stress the desirability of arriving at the minimal optimum dose for each patient.