Diverticulosis is a condition that results in pockets called diverticula that form in the walls of the digestive tract. It is common in people over the age of 60. Diverticulosis weakens the wall of the colon and can cause fistulas, as well as intra-abdominal abscesses. Additionally, alternation between constipation and diarrhea can occur. Diverticulosis may also cause painful, frequent and incomplete urination (bladder diverticulum), unexplained overgrowth/infection, and pre-cancerous intestine.