A double–blind, randomised study was performed to investigate whether aminophylline could reverse the sedative effect of benzodiazepine and if it could shorten the observation time necessary after benzodiazepine sedation. Forty patients undergoing minor abdominal, urogenital or lower extremity surgery were given benzodiazepine to maintain a state of deep sedation after spinal or epidural analgesia was achieved. Postoperatively, the patients received either aminophylline, 110 mg, or physiological saline intravenously. The aminophylline–treated patients showed a significantly more rapid reversal of sedation, but after 30 min there was no difference between the two groups. It is concluded that aminophylline antagonizes the sedative effect of benzodiazepine, but in routine benzodiazepine sedation, aminophylline will not shorten the necessary observation period after sedation.