Internal medicine concerns itself with all kinds of internal disorders, including those that involve the digestive organs.
Even more specialized is the gastroenterologist who deals solely with the digestive organs. Operative treatment is carried out by the surgeon, but invasive diagnostic procedures can be carried out by the internist or the gastroenterologist. Special methods to obtain a diagnosis are blood tests. X-rays, ultrasound and nuclear scans, biopsies and endoscopy of the stomach, small intestine and colon.