The gastrointestinal (GI) tract begins where food enters the mouth and is the long hollow tube made up by the the pharynx and oesophagus. From there it is the stomach, large and small intestines, the rectum and anus. Additionally, there are gastrointestinal accessory organs which are the salivary glands, liver and pancreas. Conditions affecting this region disrupt digestion and can sometimes lead to serious health problems if left untreated. Common conditions include: irritable bowel syndrome, hemorrhoids, colitis, acid reflux, gallstones and peptic ulcer disease.