Recovery after anaesthesia was assessed using the Maddox Wing Test (MW), Critical Flicker Fusion Threshold (CFF), Choice Reaction Time (CRT), Line Analogue Rating Scales (LARS), a Tracking Test and a test of Semantic Memory in 44 patients who had undergone minor gynaecological surgery. The patients were allocated randomly to one of two groups and received either methohexitone, nitrous oxide, oxygen and halothane or methohexitone, alfentanil, nitrous oxide and oxygen. Immediate recovery was more rapid in the alfentanil group (P less than 0.01), but apnoea (P less than 0.05) and hiccups (P less than 0.05) were more common. Except for the CFF test, which showed the alfentanil patients to be less sedated than the halothane patients on the morning after anaesthesia (P less than 0.05), the results of the tests were similar in both groups and showed, initially, substantial impairment of psychomotor functions which gradually returned to baseline values. This comparison with halothane anaesthesia indicates that a technique using methohexitone and alfentanil is suitable for day-case surgery.