If facilities for recovery are limited, shortening the recovery time from general anaesthesia is important. A comparative study on the effect of 3 mg.kg-1 aminophylline or 0.04 mg.kg-1 physostigmine on duration and quality of the recovery time from nitrous oxide-enflurane anaesthesia is presented. Three groups of 35 patients were observed, placebo being included for comparison in this double-blind study. Without treatment, recovery from nitrous oxide-enflurane inhalation anaesthesia lasted 18.8 +/- 5.80 min. Aminophylline considerably shortened the recovery time (12.06 +/- 3.52 min), whereas physostigmine did not (18.97 +/- 9.18 min). In the physostigmine group, however, a remarkably calm recovery and early return of protective reflexes was observed. Although aminophylline shortens the recovery time, due to earlier incidence of pain and other disturbances, it cannot be recommended for general improvement of recovery, whereas physostigmine clearly improves the quality of recovery from nitrous oxide-enflurane anaesthesia.