Gastrointestinal bleeding is a common complaint encountered in the emergency department and frequent cause of hospitalization. Important diagnostic factors that increase morbidity and mortality include advanced age, serious comorbid conditions, hemodynamic instability, esophageal varices, significant hematemesis or melena, and marked anemia. Because gastrointestinal bleeding carries a 10% overall mortality rate, emergency physicians must perform timely diagnosis, aggressive resuscitation, risk stratification, and early consultation for these patients.