A new topical anaesthetic formulation, EMLA, consisting of a eutectic mixture of the two local anaesthetics, prilocaine and lidocaine, was used in an attempt to reduce the pain associated with venous cannulation in children. The formulation of the local anaesthetic cream yields a high concentration (approximately 80%) of active substance compared with previous formulations (approximately 20%). A highly statistically significant difference in the experience of pain due to venous cannulation in favour of EMLA compared with placebo was found in this study (P less than 0.001) in 60 children from 6 to 15 years of age. Stimulus of C fibre endings in the subcutaneous tissue and/or the vascular wall seems to be the mechanism behind the slight to moderate discomfort experienced by about one third of the children treated with EMLA. Local side effects of EMLA were negligible.