Paediatric patients differ significantly from adults in the way that drugs affect them, for a number of reasons, including differences in their size, physiology and comorbidities. Developmental changes affecting the absorption, distribution, metabolism and excretion of many anaesthetic drugs, particularly during the first few months of life, profoundly affect both their pharmacokinetics and pharmacodynamics. Drugs discussed are the intravenous induction agents propofol, thiopental and ketamine; the sedatives dexmetetomidine and midazolam; and the opioids morphine, fentanyl and remifentanil, as well as muscle relaxants such as suxamethonium and non-depolarising relaxants. Inhalational anaesthetics are assessed for their usefulness in paediatric practice. Appropriate drug dosages are included and important differences from adult values emphasised.