Gastroenterology is the division of medicine concerned with the digestive system. This covers the oesophagus, stomach, small intestines (duodenum, jejunum, ileum) and large intestines (colon) being the human digestive tract and also the liver, pancreas and gallbladder.
Gastroenterologists are medical specialists who have training in this area. They routinely order barium X-ray studies and endoscopies for investigation of digestive tract problems.