Diverticular disease is common in Western populations, where diverticula form as outpouchings in the colonic wall. Diverticulosis refers to the presence of diverticula without inflammation, while diverticulitis occurs when diverticula become inflamed. Common symptoms of diverticulitis include severe left lower quadrant pain, fever, and leukocytosis. Complications can include abscess, fistula formation, perforation, hemorrhage, or obstruction. Diagnosis involves imaging such as CT scan or contrast enema to evaluate for complications. Treatment depends on severity but may involve antibiotics, drainage, or surgical resection.