Seclusion was used in the management of 36.6% of the patients on a general hospital psychiatric unit during a 6-mo. prospective study. It was initiated most frequently to decrease stimulation for agitated patients with poor impulse control, between 2200-0200 h and when the unit census was high. Patients requiring seclusion were significantly younger, hospitalized longer, were more often manic and received pharmacotherapy more frequently. No correlation was found between nursing staff age and psychiatric experience and the frequency that they initiated seclusion. The value of seclusion during a medication-free diagnostic assessment period is discussed.