Gastroenterology (from the Greek gastḗr- "belly", -énteron "intestine", and -logía "study of") is the branch of medicine focused on the digestive system and its disorders.

[4] Citing from Egyptian papyri, John F. Nunn identified significant knowledge of gastrointestinal diseases among practicing physicians during the periods of the pharaohs.

National Library of Medicine Catalogue (NLM classification 2006): A procedure using a long thin tube with a camera that is passed through the anus to visualize the rectum and the entire length of the colon.

A bowel prep is usually taken the night before and into the morning of the procedure which consists of an enema or laxatives, either pills or powder dissolved in liquid, that will cause diarrhea.

During the procedure, the patient is sedated and the scope is used to examine the entire length of the colon looking for polyps, bleeding, or abnormal tissue.

Complications include bloating, cramping, a reaction to anesthesia, bleeding, and a hole through the wall of the colon that may require repeat colonoscopy or surgery.

Signs of a serious complication requiring urgent or emergent medical attention include severe pain in the abdomen, fever, bleeding that does not improve, dizziness, and weakness.

[16] A procedure using a long thin tube with a camera that is passed through the mouth to view the esophagus ("esophago-"), stomach ("gastro-"), and the duodenum ("duodeno-").

Complications are rare but include reaction to the anesthesia, bleeding, and a hole through the wall of the esophagus, stomach, or small intestine which could require surgery.

[17] A procedure using a long thin tube with a camera passed through the mouth into the first part of the small intestine to locate, diagnose, and treat disorders related to the bile and pancreatic ducts.

As a result, one may experience back pain, yellowing of the skin, and an abnormal lab test showing an elevated bilirubin level which could necessitate this procedure.

However, the procedure is not recommended if the patient has acute pancreatitis unless the level of bilirubin remains high or is increasing which could suggest the blockage is still present.

After the patient is sedated, the physician will pass the scope through the mouth, esophagus, stomach, and into the duodenum to locate the opening where the ducts drain into the small intestine.

[18] A condition that is a result of stomach contents consistently coming back up into the esophagus causing troublesome symptoms or complications.

[23] Protective factors include H. pylori infection, frequent use of aspirin or other non-steroidal anti-inflammatory drugs, and diets high in fruits and vegetables.

[31] Some gastroenterology trainees will complete a "fourth-year" (although this is often their seventh year of graduate medical education) in transplant hepatology, advanced interventional endoscopy, inflammatory bowel disease, motility, or other topics.