N euroleptic malignant syndrome is characterized by hyperthermia, frequently above 41°C, extrapyramidal symptoms, changes in consciousness, autonomic dysfunction, and rhabdomyolysis, with creatine phosphokinase levels rising as high as 100,000 IU/liter [1-3]. The incidence of this idiosyncratic reaction to neuroleptic drugs occurring either at the start of, or during treatment, is between 0.4 percent and 1.4 percent [4,5], and mortality is high, ranging from 16 to 24 percent [4,6]. Apyrexia usually occurs within two to 12 days but may be deferred as long as 24 to 36 days in the case of long-acting depot neuroleptics [4,6]. The increased mortality of 40 percent associated with longacting neuroleptics may be explained by persistence of symptomatology, itself an important sign of the seriousness of the situation, and the consequential risk of intercurrent complications. The following observation is of one such case in which the patient presented with a malignant syndrome over a period of several months following treatment with haloperidol decanoate. The final outcome was satisfactory, but several complications occurred during hospitalization, notably a necrotizing enterocolitis, which considerably jeopardized vital prognosis.