The aim of this study was to explore the effects of dexmedetomidine on glucose-related hormones and lactate levels in non-diabetic patients undergoing malignant gastrointestinal tumor radical resection. Groups D<inf>1</inf> and D<inf>2</inf> received dexmedetomidine loading dose 1 µg/kg and maintenance dose 0.25 and 0.5 µg/kg/h, respectively. Group C received saline solution. Glucose, lactate, insulin, glucagon, cortisol, epinephrine, norepinephrine and dopamine levels were measured before dexmedetomidine infusion (T<inf>1</inf>), 1 h after surgery beginning (T<inf>2</inf>), at surgery ending (T<inf>3</inf>), and 1 h after transfer to the postanesthesia care unit (T<inf>4</inf>). Compared with group C, glucose levels increased in group D<inf>2</inf> at T<inf>2</inf> and reduced in groups D<inf>1</inf> and D<inf>2</inf> at T<inf>4</inf>. Lactate levels reduced in groups D<inf>1</inf> and D<inf>2</inf> at T<inf>4</inf>. A positive correlation between glucose and lactate levels was found in all groups. Compared with group C, insulin level reduced in group D<inf>2</inf> at T<inf>2</inf>; glucagon levels reduced in groups D<inf>1</inf> and D<inf>2</inf> at T<inf>4</inf>; cortisol levels reduced in group D<inf>1</inf> at T<inf>4</inf> and in group D<inf>2</inf> at T<inf>3</inf> and T<inf>4</inf>; epinephrine and norepinephrine levels reduced in group D<inf>1</inf> at T<inf>4</inf> and in group D<inf>2</inf> at T<inf>2</inf> and T<inf>4</inf>; and dopamine level reduced in group D<inf>2</inf> at T<inf>4</inf>. Dexmedetomidine loading dose 1 µg/kg and maintenance dose 0.25 µg/kg/h produces a stable insulin level and significant postoperative decreases in glucagon, cortisol, epinephrine and norepinephrine secretion with stable maintenance of intraoperative and postoperative blood glucose levels and decreased postoperative lactate levels in non-diabetic patients under general anesthesia.