Agastroenterologistis an internal medical specialist trained to diagnose, treat, and prevent gastrointestinal (GI) illnesses.
These include diseases such as:
How gastroenterologists and colorectal surgeons participate in treatment can vary.
These include:
All gastroenterologists are qualified to perform colonoscopy, sigmoidoscopy, and upper GI endoscopy.

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Additional training may be needed to perform procedures used to treat gallbladder, liver, and biliary diseases.
They can also perform minimally invasive procedures that might otherwise be done by a gastroenterologist.
University of California Irvine.Colorectal disease: conditions & treatments.
American College of Gastroenterology.What is a gastroenterologist?
National Institute of Diabetes and Digestive and Kidney Diseases.Digestive diseases.
American Medical Association.Colon and rectal surgery.
University of California Center for Colorectal Surgery.Alphabetical list procedures.