Despite the network of community mental health centers, the general hospital has become the focal point for the delivery of mental health care in the U.S. The author presents an overview of the psychiatric unit in the general hospital, including its history, structure, and function, and its relationship to the hospital itself and to the continuum of mental health services in the community. The units' goals are not clearly defined, but appear to be crisis intervention, acute treatment, correction of decompensation, prevention of chronicity, and speedy return of the patient to the community; there is little attempt to serve chronic patients. Paradoxically, the psychiatric unit also does not serve the hospital it is part of, as it rarely accepts patients from medical-surgical wards. The author summarizes evaluation studies related to general-hospital psychiatric units and recommends, among other points, truly evaluating the effects of short-term treatment and eliminating the current competition for the shortest stay.