A gastroenterologist is an internist who specializes in diagnosis and treatment of diseases of the digestive organs including the esophagus, stomach, bowels, liver, pancreas, and gallbladder. This specialist treats conditions such as abdominal pain, ulcers, diarrhea, cancer, and jaundice and performs complex diagnostic and therapeutic procedures using endoscopes to visualize internal organs. Gastroenterology also includes the discipline of hepatology--the diagnosis and treatment of liver and biliary tract diseases. Additional areas of focus include nutrition and nutritional deficiencies as well as prevention and screening, particularly for colorectal cancer. Gastroenterology requires increasingly complex decision-making; mastery of a growing number of endoscopic techniques, both diagnostic and therapeutic; an understanding of the sensitivity, specificity, risk-benefit, and cost-benefit of a broad array of diagnostic techniques and therapeutic options; and knowledge of the increasingly complex science that underlies gastroenterological practice. It is a procedure-intense specialty that requires some manual dexterity and the ability to solve problems analytically.