The role of the "heat stroke" is discussed on account of an observation of hyperthermia (42 degrees C or 107.6 Farenheit) that occured with a patient under fluphenazine decanoate, during the summer 1976 heat wave. Contrary to the American descriptions of heat strokes, the patient kept his perspiring ability. Moreover, there was no hypertonic extrapyramidal syndrome, but hypotonia instead. It is to be noted that the preliminary treatment by the corresponding standard neuroleptic (fluphenazine chlorhydrate) did not prevent that hyperthermia whose evolution was rapidly favorable.