Diverticulosis is a condition that affects the large intestine, or colon. A normal colon is strong and inner wall is relatively smooth. A colon affected by diverticulosis has weak spots in the walls. These defects allow the development of balloon-like sacs or outpouches - much like a bubble forming on a worn inner tube. These hollow pouches, called diverticulae, occur when the inner intestinal lining has pushed through weakened areas of the colon wall. A single pouch is called a diverticula.
Diverticulosis is the chronic disease without the inflammation. Pockets have developed in the large intestine but have not become inflamed and irritable, although other symptoms such as fatigue, cramps and intestinal gas may be present. When the pouches are inflamed or infected, it is called diverticulitis.