The authors studied, until the delivery, the pharmacokinetics of propofol during cesarean section. Ten patients were studied. Anaesthesia was induced and maintained with propofol (2 mg/kg in 15 seconds; 3 mg/kg/h until the end of the operation). All the patients have been intubated after the administration of atracurium 0.4 mg/kg and artificially ventilated with O2/N2O (FiO2 0.4). A series of maternal blood samples was obtained. Umbilical artery and venous blood samples have been obtained at delivery. Propofol levels in whole blood samples have been measured by a HPLC method (High pressure liquid chromatography). The results were: at delivery the mean ratio of the drug concentration in the umbilical vein to that in maternal vein was 0.53 +/- 0.16 micrograms/ml; the mean concentration in the umbilical vein was 0.96 +/- 0.31 micrograms/ml. The anaesthesiological protocol was clinically satisfactory and had no adverse effects on mother and foetus.