Objective: To investigate the effects of different anesthesiaes on the activity of aldose reductase(AR) in RBC and the levels of plasma nitric oxide(NO) in patients undergoing gastric cancer operation. Methods: Twenty-eight patients undergoing gastric cancer operation were randomly divided into two groups with 14 cases for each. Anesthesia was maintained with 1.5-2.0MAC isoflurane plus epidural block in group Ⅱ. Venous blood samples were collected to measure the AR ctivity in RBC, the levels of plasma NO and glucose.Results: The plasma levels of glucose were increased significantly at 90 min after incision and kept at the high levels till the 1st postoperative day in group Ⅰ ( P ＜ 0.01 or P ＜ 0.05) as compared with those before anesthesia, the changes in group Ⅱ were same as in group Ⅰ ( P ＜ 0.01) ,but not on the 1st postoperative day. There was no significant difference between the two groups. The activity of AR in RBC was increased significantly and the level of plasma NO was decreased significantly on the 1st postoperative day in group Ⅰ ( P ＜0.05). In group Ⅱ, AR and NO changed slightly,but these changes were not significant. The extent of change in the activity of AR or the level of NO no the 1st postoperative day in group Ⅱ was less than that in group Ⅰ ( P ＜ 0.05). Conclusion: Polyol pathway in RBC activated under surgical hyperglycemia while the production of NO is inhibited in patients undergoing gastric cancer operation, which can be effectively attenuated by combined general-epidural anesthesia.