A randomized double-blind study was performed to compare the therapeutic effects of lithium and carbamazepine (CBZ) each administered in combination with chlorpromazine (CPZ) for 3 weeks in women with acute psychosis. Thirty patients were studied. The initial dose was 1200 mg/day for CBZ and 900 mg/day for lithium, and it was subsequently modified according to plasma levels and clinical indications. The dose of CPZ was free and depended on the severity of symptomatology. Both treatments produced a significant improvement in psychotic symptoms without significant differences between the treatment groups. Also, as regards tolerability no clinically relevant differences were found between the two groups. During the first week of treatment the CPZ dose required in the CBZ group was significantly lower than that administered to the lithium group, indicating that CBZ had a greater sedative action; however, this difference decreased as treatment continued. These results confirm that CBZ is a valid alternative to lithium in the treatment of acute psychosis.