While everyone must be concerned about cancer or inflammation of the digestive tract, the commonest cause of upper or lower digestive problems are caused by alterations in the functions of the digestive tract. Upper abdominal pain and sour stomach is most often called dyspepsia and there are about 25 million people with functional dyspepsia where peptic ulcers are not present. The most common disorder of the gastrointestinal tract is the irritable bowel syndrome (IBS). The IBS is a functional disorder of the lower gastrointestinal tract, but scientific studies show that irritability or disordered function of the upper and lower digestive tract may occur together. In simple terms, disorders of function of the bowel represent a lack of harmony of the complex functions of the digestive system.