Duties of Gastroenterologist

Please tell me the duties of gastroenterologist?

This site is for home dialysis for kidney failure. Although some patients have problems with their GI tract, we are not experts in gastroenterology. I found a website by the American College of Gastroenterology that describes what a gastroenterologist is, their training, their credentials, links to health topics related to the GI tract, and to help a patient find a GI doctor.