The influence of epidural anesthesia on the endocrine-metabolic response following abdominal aortic reconstruction was studied in a prospective randomized trial. Cortisol and catecholamine responses and nitrogen balance were measured in two groups of five patients receiving general anesthesia only (group 1) or general anesthesia combined with epidural bupivacaine (group 2). The study lasted from preoperatively until the first postoperative day. At 2100 hours on the day of surgery serum cortisol concentrations were higher in group 1 than in group 2 (1.41 versus 0.82 mumol/L; p < 0.01). Likewise the total perioperative hypercortisolemia, expressed as the area under the curve, was significantly higher in group 1 (11.7 versus 5.7 mumol/L/hr, p < 0.01). Intraoperative urinary excretion of epinephrine and postoperative norepinephrine excretion were significantly higher in group 1 than in group 2. Urinary excretion of free cortisol and cumulative nitrogen balance were not different between the groups. Although the number of patients was limited and the sensory nerve block level was not measured perioperatively, this study suggests that epidural anesthesia attenuates the stress response to aortic surgery.