Crohn's disease is a condition that causes inflammation of the digestive tract and can affect any area from the mouth to the anus. It is characterized by skip lesions and non-circumferential involvement of the bowel with areas that are contracted. The rectum is often spared from the disease. Diverticular disease involves the formation of small pouches or diverticula that protrude through weak spots in the colon wall. When these pouches become inflamed it is called diverticulitis which can have complications such as fistulas, abscesses, strictures, or perforations.