BACKGROUND: There has been no consensus on the best way to prevent hypotension during epidural anesthesia. We undertook the present study to evaluate the effect of ephedrine infusion along with fluid preloading in prevention of hypotension. METHODS: Eighty patients undergoing total abdominal hysterectomy were divided into 4 groups. The Group 1 and 2 were preloaded with 1000 ml lactated Ringer's solution(LR), Group 3 with 200 ml LR, and Group 4 with 500 ml of colloid(10% pentastarch) solution. In the group 1, normal saline was infused at 12 ml/min after bupivacaine injection into epidural space. In the Group 2, 3, and 4, ephedrine(mixed in normal saline) was infused after beginning of anesthesia at 1 mg/min. RESULTS: Systolic arterial pressure after epidural blockade was significantly lower in preloading of only LR(Group 1) than those with ephedrine infusion groups(Group 2, 3, and 4). In all groups the heart rate was not changed significantly during the course of the study. The central venous pressure increased after fluid preloading in all groups, but the magnitude of increase was relatively small in Group 3. Hypotension occurred in 45% of the patients who received only LR(Group 1) vs 10% of those who received pentastarch(Group 4)(p<0.05). The incidence of hypotension(20%) was same in Group 2 and 3. CONCLUSIONS: Infusion of ephedrine could be an alternative method to prevent hypotension during epidural anesthesia. Similar incidence of hypotension in Groups 2 and 3 challenges our perception of the value of crystalloid preload.