Functional disorders are those in which the gastrointestinal (GI) tract looks normal ... Constipation and irritable bowel syndrome
One digestive disorder that affects the large intestine is called irritable bowel syndrome, or IBS. Irritable bowel syndrome is
considered a functional gastrointestinal (GI) disorder because symptoms are caused by changes in how the GI tract works.
Experts are unsure what causes IBS. However, it is a common condition that most often affects people under age 45. It affects
about twice as many women as men
