Gastroenterologists are doctors who have specialization in the diagnosis and treatment of diseases related to the stomach and intestines. They are trained in the science of gastroenterology, which is concerned with the diagnosis and treatment of conditions that affect the stomach, esophagus, small intestine, biliary system (e.g., liver, pancreas, gallbladder, bile ducts) and large intestine (colon). Gastroenterologists typically provide treatment for diseases of the digestive system including inflammation in the digestive tract, constipation, diarrhea, bleeding in the digestive tract, stomach discomfort, stomach pain, difficulty in swallowing, heartburn, stomach upset, nausea, vomiting, unexplained weight loss, ulcers, etc