PURPOSE: To evaluate the efficacy and safety of superselective arterial embolization using the microcoil in acute gastrointestinal hemorrhage. MATERIALS AND METHODS: We evaluated 11 of 42 patients who had undergone diagnostic angiography and tran-scatheter arterial embolization due to acute gastrointestinal hemorrhage and subsequently underwent superselective arterial embolization using the microcoil. Nine were males and two were females, and their age ranged from 33 to 70 (mean, 51) years. The etiologies were bleeding ulcer (n=5), pseudoaneurysm from pancreatitis (n=3), and postoperative bleeding (n=3). The symptoms were melena, hematemesis, and hematochezia, and the critical signs were decreased hemoglobin and worsening of vital signs. All patients underwent superselective embolization using the microcatheter and microcoil. RESULTS: Bleeding occurred in the gastroduodenal artery (n=5), inferior pancreaticoduodenal artery (n=2), left gastric artery (n=2), right hepatic artery (n=1), and ileal branch of the superior mesenteric artery (n=1). All cases were treated succesfully, without complications. In one case in which there was bleeding in the right he-patic artery, reembolization with a microcoil was needed because of persistent melena. During follow up, three patients died from complications arising underlying diseases, namely disseminated intravascular coagulopathy, chronic renal failure, and adult respiratory distress syndrome. Procedural complications, such as ischemia or infarction were not noted. CONCLUSION: Superselective arterial embolization using the microcoil is a safe and effective method for the treatment of acute gastrointestinal bleeding, and does not lead to complications.