In a study of 8,000 deliveries performed under continuous caudal block analgesia, the records of 741 women indicated that the combined effect of a vasoconstrictor and an oxytocic drug, given three to six hours apart, led to severe hypertension in 34 (4.6% of 741) patients. These findings suggest that the patient's need for prophylactic administration of vasoconstrictor drugs in conjunction with caudal block analgesia in obstetrics should be evaluated before giving them. Treatment with chlorpromazine hydrochloride, to prevent the severe and disabling complications of postpartum hypertension, is essential.