消化道出血在急診室是一種常見的疾病，大部份此類病患是以內視鏡檢查作為初步的診斷處置，然而，對於具有高風險臨床特徵及持續便血之病患務必考慮外科會診。我們報告急診就醫之一名76歲男子，其自半夜開始大量鮮血便且經由靜脈內輸液及輸血復甦後仍然無法穩定其血流動力學，電腦斷層血管攝影術影像發現降主動脈穿透性粥狀動脈硬化破裂合併主動脈腸室瘻管，因此施行了血管腔內主動脈瘤修復手術，病人於住院十天後平安出院。

Gastrointestinal bleeding is a common disease seen in the emergency department. In the majority of patients, endoscopy should be the initial diagnostic procedure. However, a surgical consultation should be considered in patients with high-risk clinical features and ongoing hematochezia. We present a 76-year-old man who visited the emergency department with a large, fresh, bloody stool passage at night and hemodynamic instability despite resuscitation with intravenous fluids and blood product transfusion. Computed tomography angiography showed a ruptured descending aortic penetrating atherosclerotic ulcer with aorto-enteric fistula. Endovascular aneurysm repair was performed, and the patient was discharged 10 days after admission.