A study of 405 patients revealed that the substitution of 0.1% trichloroethylene for 0.1% methoxyflurane in a previously established technique of anaesthesia led to no remarkable changes in the incidence of postoperative nausea, vomiting or headache. There was, however, an increase in the incidence of awareness from 3.5% to 5.1%. There was no significant difference in the Apgar scores (totals or individual components) or in the materno-foetal acid-base gradients at delivery between the Group A elective Caesarean section patients in the two series. In view of these findings, and of the relative freedom from toxicity and the inexpensiveness of trichloroethylene, a more general re-introduction of the drug into anaesthetic practice is advocated. The study also served to demonstrate that, using the technique described, the duration of the interval from induction of anaesthesia to the initial incision into the myometrium was, at least up to 30 min, of no significant import to the well-being of the infant, but that the time elapsing between uterine incision and complete delivery was directly and significantly associated with neonatal asphyxia and clinically-apparent depression of the infant.