http://www.gastro.org/

The American Gastroenterological Association (AGA) is dedicated to the mission of advancing the science and practice of gastroenterology. Founded in 1897, the AGA is the oldest medical-specialty society in the United States. Comprised of two non-profit organizations - the AGA and the AGA Institute - our 15,500 members include physicians and scientists who research, diagnose and treat disorders of the gastrointestinal tract and liver.