This document discusses gastrointestinal bleeding, focusing on upper GI bleeding (UGIB) and lower GI bleeding (LGIB). It covers the typical presentation, evaluation, and management of acute UGIB and LGIB. For UGIB, initial management involves hemodynamic stabilization, upper endoscopy to identify the source within 12 hours, and endoscopic therapy if possible. For high risk lesions, angiography or surgery may be needed. For LGIB, initial steps are the same while colonoscopy is preferred for evaluation once stable, though angiography can be used if bleeding is ongoing. Most episodes of UGIB and LGIB stop spontaneously without intervention.