Gastroenterology (MeSH heading) is a branch of medicine focused on the digestive system and its disorders. The name is a combination of three Ancient Greek words gaster (gen.: gastros) (stomach), enteron (intestine), and logos (reason). In the U.S., Gastroenterology is an Internal Medicine Subspecialty certified by the ABIM.

Diseases affecting the gastrointestinal tract, which includes the organs from mouth to anus, along the alimentary canal, are the focus of this specialty. Physicians practicing in this field of medicine are called gastroenterologists.