A gastroenterologist is a doctor who specializes in diseases of the digestive system, including the esophagus, stomach, intestines, colon and rectum, pancreas, gallbladder, bile ducts, and liver. It is responsible for diagnosing and treating conditions such as gastroesophageal reflux, ulcers, inflammatory bowel diseases, irritable bowel syndrome, hepatitis, pancreatitis and liver diseases. It is advisable to see a gastroenterologist if persistent symptoms such as abdominal pain, difficulty swallowing, heartburn, diarrhea, constipation, jaundice or digestive bleeding occur.