Lower gastrointestinal bleeding (LGIB) continues to be a problem for physicians. Acute LGIB is defined as bleeding that emanates from a source distal to the ligament of Treitz. Although 80% of all LGIB will stop spontaneously, the identification of the bleeding source remains challenging and rebleeding can occur in 25% of cases. Some patients with severe hematochezia require urgent attention to minimize further bleeding and complications. This article reviews the causes, diagnostic methods, and endoscopic treatment of LGIB.