BACKGROUND: The present study was designed to assess the effects of preemptive epidural analgesia on postoperative peripheral WBC response and pain in patients undergoing laparoscopic hysterectomy under general anesthesia. METHODS: Patients were randomly assigned to one of two groups; a preemptive epidural group (Pre-E group, n = 25) or a postoperative epidural group (Post-E group, n = 25). In the Pre-E group, 10 ml of 1% lidocaine and 2 mg morphine were given to achieve T6-level sensory block via an epidural catheter before the induction of anesthesia, but this was not done in the Post-E group. Postoperative pain was assessed by patients using VAS, and venous blood samples were collected four times throughout the study period (30 minutes before induction, immediately after surgery, and on postoperative days 1, and 3). RESULTS: Pain scores 1, 3, and 6 hours after surgery were significantly lower in the Pre-E group than in the Post-E group, but became similar 12 hours after surgery. Significantly more patients requested additional analgesics in the Post-E group (24%) than in the Pre-E group (0%). Monocyte percentages differed significantly in the two groups at 1 day after surgery. However, total WBC counts and percentages of neutrophils, lymphocytes, eosinophils, and basophils were similar in the two groups. CONCLUSIONS: Preemptive epidural analgesia provides more effective postoperative pain control, but shows no significant beneficial effect with respect to postoperative WBC response in patients undergoing general anesthesia for laparoscopic hysterectomy.