Section 1: Criteria for assessing recovery after anaesthesia: Introduction; The problems defined; Alcohol and the law; Alcohol as a comparator; Anaesthetic impairment and the law; Measuring post-anaesthetic impairment of mental function; Section 2: Methods of assessment: The autonomic nervous system; Neuromuscular function; Saccadic eye movements; Body sway; Performance tests: vigilance and reaction time; Inspection time; Memory function; Subjective assessment; Section 3: Impairment of personnel after acute drugs: An occupational physician's view; Elderly patients; Paediatric patients; Section 4: Problems - acute drugs and performance/recovery: Benzodiazepines; Opioids and non-opioids; Intravenous anaesthetics; Inhalation anaesthetics; Section 5: Testing new drugs for improved recovery or outpatient use: Anaesthetic agents; Tranquillizers and sedatives; Conclusion