Lower gastrointestinal bleeding (LGIB) is a frequent reason for hospitalization especially in the elderly. Patients with LGIB are frequently admitted to the intensive care unit and may require transfusion of packed red blood cells and other blood products especially in the setting of coagulopathy. Colonoscopy is often performed to localize the source of bleeding and to provide therapeutic measures. LGIB may present as an acute life-threatening event or as a chronic insidious condition manifesting as iron deficiency anemia and positivity for fecal occult blood. This article discusses the presentation, diagnosis, and management of LGIB with a focus on conditions that present with acute blood loss.