Diverticular disease includes a spectrum of conditions sharing the underlying pathology of acquired diverticula of the colon: symptomatic uncomplicated diverticular disease, recurrent symptomatic uncomplicated diverticular disease, and complicated diverticular disease. Goals of therapy in diverticular disease should be to improve symptoms and to prevent recurrent attacks in symptomatic uncomplicated diverticular disease, and to prevent the complications of disease such as diverticulitis. Inflammation seems to play a key role in all forms of the disease. This is the rationale for the use of anti-inflammatory drugs such as mesalazine. Inflammation in such diseases seems to be generated by a heightened production of proinflammatory cytokines, reduced anti-inflammatory cytokines, and enhanced intramucosal synthesis of nitric oxide. The mechanisms of action of mesalazine are not yet well understood. It is an anti-inflammatory drug that inhibits factors of the inflammatory cascade (such as cyclooxygenase) and free radicals, and has an intrinsic antioxidant effect. Some recent studies confirm the efficacy of mesalazine in diverticular disease both in relief of symptoms in symptomatic uncomplicated forms and in prevention of recurrence of symptoms and main complications.