Thirteen patients undergoing lower abdominal gynaecological surgery were allocated to general anaesthesia (halothane and nitrous oxide) or general anaesthesia plus extradural analgesia (T8-S5). I.v. glucose tolerance tests were performed on the day before surgery and 8 h after skin incision. All patients having extradural analgesia (T8) were pain-free following surgery. Extradural analgesia blocked the hyperglycaemic response to surgery but not the late postoperative cortisol response, although values were significantly less than in the group receiving general anaesthesia alone. Impairment of glucose tolerance and of insulin response to the glucose load in the period after operation were not influenced by extradural analgesia and this may have resulted from insufficient inhibition of the stress-induced release of catecholamines or cortisol, or both, or from blockade of stimulatory efferent sympathetic pathways to pancreatic islets.