The relevant physiological and pharmacokinetic differences between adults and infants and children are considered, and the advantages and disadvantages of the available inhalational anaesthetics are discussed. Desflurane shows promise as a new paediatric anaesthetic as it allows rapid changes in the depth of anaesthesia. However, irritant effects on the airways make desflurane unsuitable for induction. Desflurane anaesthesia, following halothane induction, seems to be well tolerated.