Blood concentrations of glucose, lactate, non-esterified fatty acids (NEFA) and insulin (IRI) were measured in two groups of ten patients undergoing elective gastrectomy under general anesthesia with halothane (Group G) or epidural analgesia extending from Th3-4 to L1-2 without halothane (Group E). The rise in blood glucose and the rise in NEFA in group E during operation were significantly less than in Group G. Blood lactate levels during operation were lower in group E than in group G although the difference was not statistically significant. The increase in IRI/glucose ratio on postoperative day 1 was significantly less in Group E than in Group G, suggesting that insulin sensitivity after surgery was higher in Group E. The postoperative course was uneventful in all subjects. These results suggest that the endocrine-metabolic response to major upper abdominal surgery can be inhibited by epidural analgesia.