A physician can determine whether decreasing or replacing certain food products or taking enzyme supplements can provide the needed digestive support. The GI tract also contains the largest immune system in the body, defending it against potentially pathogenic microorganisms that find their way into the body through food, drink and the environment. In Inflammatory Bowel Disease (IBD), the immune system reacts to normal tissue and harmless microbes as well as harmful invaders. This autoimmune response damages GI tract tissue leading to diarrhea, bleeding and other symptoms. Crohns disease causes inflammation deep in the lining of the small intestine, inducing pain and chronic diarrhea. It can be a difficult disease to diagnose because its symptoms are similar to other intestinal disorders such as irritable bowel syndrome and to another type of IBD called ulcerative colitis. Ulcerative colitis causes inflammation and ulcers in the top layer of the lining of the large intestine.. When to see a Doctor for Stomach Pain Though normal bowel habits will differ among individuals, it is important to be aware of changes that persist or appear abruptly. Drugs and surgery for digestive disease do not generally work to restore the harmony of the GI system, but are necessary for diseases that alter the structure of the bowel, for example cancer and certain types of inflammation and other serious disorders. However, if left untreated, even minor disorders can prevent optimal digestion and nutrient absorption resulting in severe vitamin and mineral deficiencies in the body. It is critical to see your doctor if you experience the following recurring symptoms without obvious reasons: abdominal pain or cramping before or after meals, feelings of fullness, bloating or gassiness, nausea or vomiting, pain or difficulty in swallowing, loss of appetite, drastic unexplained weight loss, indigestion, bleeding or pain when passing waste, feeling that the bowels are not emptying completely and diarrhea, constipation and any chronic change in bowel habit. Diarrhea and the dehydration it causes, can be a serious problem for anyone, but is especially life-threatening for young children and the elderly. A doctor must be consulted if diarrhea persists or if it is accompanied by symptoms of severe abdominal pain, a high fever or blood or mucus.