Gastroenterology is the study of the normal function and diseases of the esophagus, stomach, small intestine, colon and rectum, pancreas, gallbladder, bile ducts and liver. It involves a detailed understanding of the normal action (physiology) of the gastrointestinal organs including the movement of material through the stomach and intestine (motility), the digestion and absorption of nutrients into the body, removal of waste from the system, and the function of the liver as a digestive organ. It includes common and important conditions such as colon polyps and cancer, hepatitis, gastroesophageal reflux (heartburn), peptic ulcer disease, colitis, gallbladder and biliary tract disease, nutritional problems, Irritable Bowel Syndrome (IBS), and pancreatitis. In essence, all normal activity and disease of the digestive organs are part of the study of Gastroenterology. The unique training that Gastroenterologists complete provides them with the ability to provide high quality, comprehensive care for patients with a wide variety of gastrointestinal ailments. Gastroenterologists perform the bulk of research involving gastrointestinal endoscopic procedures as well as the interpretation of results, and are considered experts in the field.