Gastroenterology or gastrology is the medical specialty concerned with digestive diseases. It is popularly (and incorrectly) known as "GI" (which stands for gastrointestinal).

A gastroenterologist is a physician who specialises in the diagnosis and treatment of disorders of the gastrointestinal tract, including the oesophagus, stomach, small intestine, large intestine, pancreas, liver, gallbladder, and biliary system.