Increased intestinal permeability is one of the main pathophysiological mechanisms involved in irritable bowel syndrome. The expression of some intestinal tight junction proteins is decreased mostly in IBS-diarrhoea patients. This decrease is correlated with increased intestinal permeability. Currently, no test used in clinical practice could assess intestinal permeability.

We hypothesis plasmatic zonulin could reflect intestinal permeability in IBS patients.

The goal of our study is to look for a correlation between plasmatic zonulin and increased colonic permeability (assessed by the expression of intestinal tight junction proteins by western blot) in IBS patients and to look for a role of intestinal low-grade inflammation and microbiota.

Population :

IBS patients with diarrhoea or IBS with constipation or mixed with worsening of symptoms

Outcomes measures :

Plasmatic zonulin (ELISA kit) Occludin expression in colonic biopsies (western blot)

Inclusion Criteria:

• IBS-Diarrhoea, IBS-constipation or alternating with recent worsening of symptoms, according to Rome III criteria
• Effective contraception since 1 month for women in childbearing age

Exclusion Criteria:

• Patients with organic and/or inflammatory digestive disease
• IBS with constipation or alternating without clinical warning sign
• Treatment such as anti-inflammatory, probiotic in the last three months
• Severe renal failure
• Hypersensitivity to Normacol
• Patient with blood dyscrasia disorder known or identified, anticoagulant or antiplatelet treatments
• Anal pathology (anal fissure, hemorrhoidal thrombosis)
• Pregnant or breastfeeding women
• Person with administrative or judicial decision or under legal protection measure
• Patient participating in another trial in the last two weeks