Cocaine abusers may present to emergency care systems with a variety of symptoms resembling various neuropsychiatric syndromes. The differential diagnostic assessment of these patients can prove quite challenging.Several other factors further complicate the evaluation process when cocaine is suspected. The coexistence of substance abuse and other psychiatric disorders has been well described (5,14) and must be considered for accurate diagnostic formulation. In addition, in this era of widespread substance abuse, emergency practitioners must consider other substance-specific intoxication and withdrawal syndromes in assessing most patients presenting for care with acute mental status changes. Moreover, a significant proportion of cocaine abusers are polysubstance abusers; they may present with mixed and confusing features and thus warrant detoxification considerations.Cocaine remains a significant drug of abuse in this country. A better understanding of cocaine's physiological and behavioral manifestations is critical for front-line practitioners. Prompt recognition of a cocaine-induced neuropsychiatric syndrome allows the development of an appropriate treatment plan, and, most important, reduction in morbidity and mortality.