Two series of 25 patients who underwent elective Caesarean section with general anaesthesia were given either 0.75% isoflurane or 0.5% halothane as supplements to 50% nitrous oxide in oxygen used for maintenance. The potent inhalational agent was given for the entire operative period and no case of intra-operative dreaming or awareness was reported. The infusion dose of suxamethonium was significantly less with isoflurane, 50 micrograms/kg/minute (SD 17), as compared to halothane, 64 micrograms/kg/minute (SD 24) (p less than 0.02). Recovery from anaesthesia was more rapid with isoflurane. The surgeon's assessment of uterine relaxation and bleeding using a visual analogue score indicated that this was significantly less with isoflurane. Infant well-being as judged by Apgar score and cord blood gas analysis, showed little difference between the two inhalational agents.