Ephedrine sulfate was administrated 30 healthy parturients undergoing elective repeat cesarean section under spinal anesthesia. Fifteen patients received ephedrine infusion (0.01% solution, beginning with approximately 5 mg/min) immediately after induction of spinal anesthesia to maintain maternal systolic blood pressure between 90% and 100% of the baseline systolic blood pressure (mean dose of ephedrine 31.6mg). Fifteen patients (contral group) received 20mg of ephedrine as an intravenous bolus, and additional 10mg increments, if neccessary, when systolic blood pressure decreased to 80% of the baseline systolic blood pressure (mean dose of ephedrine 26.8 mg). Nausea and/or vomiting occurred in seven women in the control group and one patient in the infusion group (p<0.001). Apgar scores, fetal blood gas tension, and time for onset of respiration was comparable in the two groups. The results suggest that prophylactic ephedrine infusion is safe and desirable in healthy parturients undergoing cesarean section under spinal anesthesia.