Colonic diverticulitis is the inflammation or infection of small pouches (diverticula) that form in the colon wall. These diverticula develop due to weak spots in the colon, often related to aging or a low-fiber diet. When these pouches become inflamed, it causes abdominal pain, fever, and digestive issues. Early diagnosis and treatment are crucial to prevent complications like abscesses or perforation of the colon.