Medical and surgical inpatients with coexisting psychiatric disorders pose several challenges to the consulting mental health professional in the general hospital. A major challenge is determining whether presenting signs and symptoms have a medical or psychiatric basis. Making such a determination requires a careful history, a mental status examination, and the utilization of bedside screening and diagnostic instruments. Recommended treatments include psychotherapy, psychoeducation, and pharmacotherapy. However, psychotropic drugs must be used with caution because of potential interactions with drugs prescribed for medical conditions. Studies indicate that timely psychosocial interventions can improve the medical patient's mental health and have the potential to reduce length of hospital stay and utilization of health services.