We describe four major and five minor clinical patterns of acute phencyclidine (PCP) intoxication and give the incidence of findings in each pattern. Major patterns were acute brain syndrome (248 cases; 24.8%), toxic psychosis (166 cases; 16.6%), catatonic syndrome (117 cases; 11.7%), and coma (106 cases; 10.6%). Minor patterns included lethargy or stupor (38 cases; 3.8%), and combinations of bizarre behavior, violence, agitation, and euphoria in patients who were alert and oriented (325 cases; 32.5%). Patients with major patterns of PCP toxicity usually required hospitalization and accounted for most complications. In general, patients with minor patterns had mild intoxication and did not require hospitalization except for the treatment of injuries or autonomic effects of PCP. Various types of injuries occurred in 16%, and aspiration pneumonia occurred in 1.0% of all cases. There were 22 cases of rhabdomyolysis (2.2%), with three patients requiring dialysis for renal failure. One patient who had been comatose from PCP died suddenly. A fresh pulmonary embolism was found at autopsy.