To determine whether the type of peri-operative analgesic regimen affects the metabolic response during and after surgery, we studied 19 women undergoing abdominal hysterectomy under propofol anaesthesia. Patients were randomized to receive either continuous intravenous opioid or a bupivacaine-opioid mixture through a lumbar epidural catheter. Total body oxygen consumption and carbon dioxide excretion, blood glucose and haemodynamic variables were determined up to 24 h after surgery. No differences in any metabolic or haemodynamic variables were noted during surgery. In the post-operative period, the increase in oxygen consumption up to pre-operative values, the urinary nitrogen excretion and the changes in acute phase proteins were similar in both treatment groups. In contrast, the respiratory quotient was significantly higher in the lumbar epidural group than in the intravenous opioid group, 0.87 (SD 0.04) vs 0.77 (SD 0.06) (P < 0.05) and the hyperglycaemic response was more delayed in the epidural group. These data suggest that prolonged sympathetic blockade associated with epidural analgesia might contribute to better preservation of glucose homeostasis in the perioperative period.