One of your body's most important systems is your digestive tract. It often works fine without a problem, but small pouches can develop in the colon. These small pouches can form when the inside layer of the tract pushes out through a weak spot. They can be found anywhere along the tract. Most often, they occur on the left side of your large intestine. This area is known as the descending and sigmoid colon. The pouches are known as diverticulosis. When one or more of these pouches gets inflamed, the condition is called diverticulitis.