Gamma-hydroxybutyric acid was used as a sedative for 54 children undergoing cardiac catherization and as a form of anaesthesia in 159 children undergoing paediatric surgery and various paediatric investigations. In 16 of the cardiac group and 22 of the surgical group, an assessment of blood-gas status was made. Clinical impressions were favourable and the biochemical findings underline the safety, efficacy and usefulness of this drug in paediatric practice.