Substance abuse among the mentally ill has become increasingly prominent. This article describes the problems presented by dual diagnosis patients in the urban, publicly funded, psychiatric emergency room. When such patients become acutely ill, neither the public health system nor the mental health clinician is adequately prepared to provide care. The inability to effectively treat these patients has become strikingly clear in recent years. In 1986, the Psychiatric Emergency Service at San Francisco General Hospital began to overflow with patients who required overnight stays. The intoxicated substance abusers with acute psychiatric complaints were the most difficult to manage clinically and administratively. Suggestions are offered for innovative approaches to this group of public patients: dual training of clinicians, flexible treatment programs prepared to deal with the whole person, and public funding that reflects patients' needs rather than clinicians' preferences.