The aim of this work was to compare the recurrence of diverticulitis during a 5-year follow-up in a population of patients affected by symptomatic uncomplicated diverticular disease (SUDD), taking either 800 mg of mesalamine b.i.d for 10 days every month or no 5-ASA. Sixty-seven consecutive patients affected by SUDD followed-up every 6 months for 5 years. All patients in this group (M-group) were requested to consume mesalamine 800 mg b.i.d for 10 days every month. A control group (C-group) of 82 subjects with SUDD allocated in an institution for the elderly and taking no 5-ASA medications was also followed-up for the same period. As a result in the M-group 14.9% of patients did not complete the follow-up, and diverticulitis developed in two patients (4%; 95% CI 1.1-13.5). In the C-group 6.1% patients did not complete the follow-up, and diverticulitis developed in 8 patients (10.4%; 95% CI 5.4-19.2). The difference between the two groups was not significant (difference = -6.4%; 95% CI -15.6 to 4.3; log rank test: p = 0.1256). Cyclic treatment with mesalazine seems to be clinical, although not statistically effective in reducing the incidence of diverticulitis. In future well-designed RCTs are necessary to demonstrate the therapeutic gain of the use of mesalazine, if any, in the management of patients with SUDD.