['The frequency of emergence agitation in children is increased following sevoflurane anesthesia. However, controversies still exist concerning the exact etiology of this postanesthetic problem. Although this phenomenon is present with adequate pain relief or even following pain-free procedures, pain is still regarded as a major contributing factor.', 'In a prospective, randomized, double-blind study, we enrolled 48 premedicated and calm 2-6-year-old children undergoing inguinal hernia repair. We assigned children to one of two groups: children assigned to the caudal group (n = 24) received a caudal block to supplement sevoflurane, while children assigned to the fentanyl group (n = 24) received a bolus injection of 1 microg kg(-1) intravenous fentanyl before skin incision to supplement sevoflurane. In the post anesthesia care unit, all children were received by their parent, and the incidence of emergence agitation and pain scores, as well as hemodynamic changes, were compared in both groups.', 'Forty-four children completed the study. In the fentanyl group, 59% of the children were agitated following emergence from anesthesia as compared to 4.5% in the caudal group (P < 0.001). Also, pain scores, mean values of heart rate and blood pressure as well as morphine requirement were significantly higher in the post anesthesia care unit in the fentanyl group compared to the caudal group.'] Does preoperative caudal block prevent emergence agitation in children following sevoflurane anesthesia?