To investigate the combined metabolic effects of beta-mimetic therapy and general anesthesia on maternal and fetal/neonatal metabolism, 14 patients were treated with isotonic saline, 11 with intravenous fenoterol (3 microgram/min) and 9 with intravenous isoxsuprine (150 microgram/min) for 30 minutes prior to cesarean section. The maternal heart rate and blood pressure as well as the maternal and fetal acid-base balance were followed. The neonatal glucose level was monitored for 36 hours after delivery. The heart rate and the diastolic and systolic blood pressure values increased during the operation in each group, without any marked differences between the groups. At delivery, the mean maternal BD (base-deficit) value was higher in the fenoterol patients than in the control patients, indicating a trend towards metabolic acidosis. The other values of acid-base balance in the maternal and umbilical arterial and venous blood did not reveal any differences between the groups. The neonatal glucose level at 2 hours after delivery was higher in the fenoterol group than in the control group. The other values recorded during 36 hours revealed no differences between the groups. Beta-mimetic treatment preceding general anesthesia in cesarean section does not have unfavorable effects on the mother, the fetus or the newborn. Such therapy thus does not seem contraindicated when uterine contractions should be rapidly suppressed in cases of fetal distress before operation.