The recovery of cranial nerve reflexes was evaluated sequentially in time during the efforts at resuscitation in 111 victims of circulatory arrest of primary cardiovascular or pulmonary origin. Fifty-seven patients had some brain function when life support was initiated (Group I) while 54 had at first no such function (Group II). Recovery occurred in a fixed order, irrespective of the initial neurological status or subsequent outcome: spontaneous respiratory movements were either present or were the first function to return; thereafter followed pupillary light reflexes, coughing-swallowing, and ciliospinal reflexes, in that order. Orderly recovery was featured by a time-related return of reflexes and consciousness while abnormal courses were characterized by stagnation of the recovery process, lack of time-related return of and loss of function. Prognostic rules were similar for the two population groups. Reflex tests at 10-60 min of resuscitation differentiated patients who would regain consciousness from those remaining unconscious with sensitivities and specificities > or = 80. A positive pupillary response or coughing-swallowing at 10 min, or ciliospinal reflex at 20 min predicted return of consciousness with positive predictive values of 0.85-1.00 (prior odds 0.29) while negative tests at 20-30 min indicated failure of complete recovery with values of 0.94-100 (prior odds 0.89).