This is a multi-centre, randomised, double blind, double-dummy, parallel groups, placebo-controlled trial was conducted in a population of patients suffering from symptomatic uncomplicated diverticular disease in order to investigate which is the best treatment in preventing relapses of the disease.

Patients were randomly divided in double-blind fashion in one of the following groups:

Group A. Active mesalazine 800 mg, 2 tablets/day for 10 days/month plus Lactobacillus casei placebo, 1 sachet/day for 10 days/month;

Group B. Active Lactobacillus casei, 1 sachet/day for 10 days/month plus mesalazine 800 placebo, 2 tablets/day for 10 days/month;

Group C. Active mesalazine 800 ng, 2 tablets/day plus Active Lactobacillus casei, 1 sachet/day for 10 days/month;

Group D. Mesalazine 800 mg placebo, 2 tablets/day and Lactobacillus casei placebo, 1 sachet/day for 10 days/month.

The main objective was to assess the safety and the efficacy of mesalazine and/or Lactobacillus casei in maintaining remission of symptomatic uncomplicated diverticular disease

Inclusion Criteria:

• diagnosis of diverticular disease diagnosed for the first time or established by previous colonoscopy
• symptomatic episode of uncomplicated diverticular disease no more than 4 weeks prior to study entry
• patients who have given their free and informed consent.

Exclusion Criteria:

• acute diverticulitis (both complicated and uncomplicated)
• diverticular colitis
• active or recent peptic ulcer
• chronic renal insufficiency
• allergy to salicylates
• patients with intended or ascertained pregnancy, lactation
• women of childbearing age not using contraceptives
• lactulose-lactitol use in the two weeks before the enrolment and during the study
• presence of diverticulitis complications (fistulas, abscesses, and/or stenoses)
• use of probiotic preparations either prescribed or over-the counter within two weeks prior to study entry
• inability to give a valid informed consent or to properly follow the protocol
• patients with active malignancy of any type, or history of a malignancy (patients with a history of other malignancies that have been surgically removed and who have no evidence of recurrence for at least five years before study enrolment were also acceptable)
• recent history or suspicion of alcohol abuse or drug addiction
• any severe pathology that can interfere with the treatment or the clinical or instrumental tests of the trial
• use of NSAIDS for one week before and throughout the study period (only paracetamol was permitted).