Overview of Gastrointestinal Bleeding By Parswa Ansari, MD, Hofstra Northwell-Lenox Hill Hospital, New York Reviewed / Revised May 2023 View Patient Education Etiology Evaluation Treatment Geriatrics Essentials Key Points More Information Topic Resources Lower GI Bleeding and Risk... CT Angiography Showing Gastrointe... Common Causes of Gastrointestinal... Gastrointestinal (GI) bleeding can originate anywhere from the mouth to the anus and can be overt or occult.