The Anaesthesia and Brain activity Monitor was used to determine if any electroencephalographic variation becomes evident following the administration to patients of either atropine sulphate or glycopyrrolate when given with neostigmine to reverse a non-depolarising neuromuscular blockade. The apparatus was also used to study possible earlier arousal times by electroencephalography and electromyography in those patients who had received glycopyrrolate with neostigmine compared with those who had atropine as an anticholinergic. The apparatus was not sensitive enough to detect changes resulting from atropine injection but clearly demonstrated earlier arousal times by electromyography in patients who had received glycopyrrolate.