Table Common Causes of Gastrointestinal (GI) Bleeding Upper GI tract Duodenal ulcer (20 - 30%) Gastric or duodenal erosions (20 - 30%) Varices (15 - 20%) Gastric ulcer (10 - 20%) Mallory-Weiss tear (5 - 10%) Erosive esophagitis (5 - 10%) Angioma (5 - 10%) Arteriovenous malformations (< 5%) Gastrointestinal stromal tumors Hemobilia Lower GI tract (percentages vary with the age group sampled) Anal fissures Angiodysplasia (vascular ectasia) Colitis: Radiation, ischemic, infectious Colonic carcinoma Colonic polyps Diverticular disease Inflammatory bowel disease: Ulcerative proctitis / colitis, Crohn disease Internal hemorrhoids Small-bowel lesions (rare) Angiomas Arteriovenous malformations Meckel diverticulum Tumors Evaluation of GI Bleeding In acutely ill patients, stabilization with airway management, IV fluids, or transfusions is essential before and during diagnostic evaluation.