46 severely depressed inpatients received 10-hour intravenous infusions supplying a dose of 720 mg dibenzepin daily on 2 or some cases 3 successive days. The patients were kept under close psychiatric surveillance and their cardiovascular function was carefully monitored. The shorter infusions were as effective as infusions of the same dose of Noveril over 48 h, and did not lead to a greater frequency or severity of general or cardiovascular side effects. The 10-hour infusion regimen thus represents a new mode of treatment for severe depression which is less demanding both technically and in terms of nursing care.