IRCT20151106024901N5 IRCT 2021-08-24 Tabriz University of Medical Sciences Clinical efficacy of Mesalazine in patients with diarrhea-dominant irritable bowel syndrome with elevated fecal calprotectin referred to Emam Reza Hospital of Tabriz: a randomized double-blind, placebo-controlled trial Clinical efficacy of Mesalazine in patients with diarrhea-dominant irritable bowel syndrome with elevated fecal calprotectin referred to Emam Reza Hospital of Tabriz: a randomized double-blind, placebo-controlled trial 2021-01-20 anticipated 90 Complete https://irct.ir/trial/53050 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Randomization description: Randomization method: simple. Randomization unit: individual. Randomization tool: sealed envelope َThe researcher assigned individuals into two groups using lottery (selecting sealed envelopes, with a card with the letters M or C inside them), Blinding description: In this study, the patient and the researcher are kept blind. In this way, the safety and data monitoring committee know whether it is a placebo or a drug, and the researcher and the patient do not know the type of group. In this regard, the drug and the placebo will be packed in the same boxes. The drug and placebo will be packaged and delivered by the committee in separate envelopes, and the researcher will divide the patients into two groups, by giving envelope A or envelope B. 3 Irritable Bowel Syndrome. Intervention 1: Intervention group: 500 mg mesalazine tablets 2 times a day for 8 weeks and patients 'clinical manifestations will be evaluated by a physician. Intervention 2: Control group: received placebo 2 times a day for 8 weeks and patients 'clinical manifestations will be evaluated by a physician. No - There is not a plan to make this available Justification or reason for not sharing IPD is There is no more information.