A gastroenterologist is a doctor who specializes in treating diseases of the digestive tract, according to the American Gastroenterological Association. The digestive system consists of the intestines, liver, pancreas and gallbladder, and it is responsible for breaking down and absorbing food.
Gastroenterologists are highly trained specialists, explains the American Gastroenterological Association. Following four years of medical school and a three-year internal medicine residency, they complete a thorough two- to four-year fellowship in gastroenterology. Some of the illnesses treated by gastroenterologists include colorectal cancer, irritable bowel syndrome, diverticulitis, heartburn and appendicitis. Two tests commonly performed by gastroenterologists are the colonoscopy and the upper-gastrointestinal endoscopy.