Anaesthetic mortality was assessed in 21,500 children and 7,200 adults undergoing dissection tonsillectomy and/or curettage of the adenoids. There was one such death amongst the children; none amongst the adults. The children were anaesthetized by an insufflation technique using a Boyle-Davis gag and ether in the majority of cases; nasotracheal tubes were used in all adults. The dangers inherent in the use of an insufflation technique are outlined, but it is considered that with care and vigilance it is, for such operations, reasonably safe. For use in the technique, the safety of ether is generally confirmed, and a possible danger with regard to halothane is mentioned. Previous reports on mortalities in tonsillectomy and adenoidectomy are reviewed and discussed.