A 57-year-old man, who had undergone a Billroth I partial gastrectomy for a duodenal ulcer 1 year previously, was hospitalized for continual epigastric pain over the past 1 month. Laboratory testing revealed anemia (hemoglobin 9.4g/dL; normal range 13.5–16.9) and an elevated Creactive protein level (2.22mg/dL; normal <0.02). Liver function tests and the serum gastrin level were within normal limits. Abdominal ultrasound revealed fluid and air bubbles in the liver (●" Fig.1a), moving between the liver and stomach through a fistula (●" Fig.1b). Computed tomography (CT) verified the ultrasound findings (●" Fig.2). Endoscopy revealed a large ulcer in the duodenum near the anastomosis (●" Fig.3). An endoscopic biopsy of the ulcer was negative for malignancy. The patient was diagnosed as having a stomal ulcer that had penetrated the liver, and he was subsequently treated with an H2 blocker and intravenous antibiotics. The ulcer healed after 1 month of treatment (●" Fig.4). After discharge, the patient continued to take proton pump inhibitors (PPIs), and there has been no recurrence of the ulcer during the 7-year follow-up period. The most common site of penetration by duodenal ulcers is the pancreas (52.6%), followed by the biliary tract (18.4%), gastrohepatic omentum (10.7%), liver (6.2%), and colon (1.5%) . Most cases of hepatic penetration have been diagnosed intraoperatively and/or by endoscopic biopsy [1,2]. However, in our patient, the ultrasound clearly demonstrated detailed findings sufficient for diagnosis. Most cases of ulcers penetrating the liver have been treated by surgical procedures [1,2]. In addition to the present report, there have been two other recent case reports that have demonstrated the effectiveness of medical treatments such as H2 blockers and PPIs [3,4].