This investigation was undertaken to determine whether acute psychiatric admissions to hospital were in any way influenced by the premenstruum or by menstruation. Admission records to psychiatric facilities were examined to determine the patients last menstrual period. Data indicated 39% of suicide attempts occurred during menstruation. Admissions were greatly increased for depressed & schizophrenic patients during menstruation. Completed suicides were more common during the luteal phase. (NBB)