Upper GI bleed occurs proximal to the ligament of Treitz, while lower GI bleed occurs distal to it. Acute upper GI bleeding causes hematemesis or melena, while lower GI bleeding presents as hematochezia. In the ER, management of acute GI bleeding involves stabilizing ABCs, administering IV fluids and blood products, and performing tests like CBC, INR, and UGI endoscopy once stabilized. Later management may include identifying the bleeding source, treating with drugs like PPIs or vasopressors, or pursuing interventions like TIPS or surgery if bleeding persists. Obscure GI bleeding has no identified source on initial endoscopy and workup may involve repeated endoscopy, capsule end