Ibodutant for Relief of Irritable Bowel Syndrome (IRIS)

Inclusion Criteria: 1. Male or female patients aged 18 - 70 years. 2. Clinical diagnosis of IBS . 3. For patients older than 50 years or patients with positive family history of colorectal cancer: normal results from colonoscopy or flexible sigmoidoscopy. 4. Use of appropriate contraceptive methods. 5. Normal physical examination or without clinically relevant abnormalities. Exclusion Criteria: 1. Patients with organic abnormalities of the gastro-intestinal tract including history of colonic or major abdominal surgery, current or previous diagnosis of neoplasia, inflammatory bowel diseases, symptomatic gallbladder stone disease, diverticulosis/diverticulitis, ectopic endometriosis. 2. History of gluten enteropathy. 3. Lactose intolerance as assessed by response to diet 4. Diagnosis of ova or parasites, or occult blood in the stool in the previous 6 months. 5. Previous diagnosis of Diabetes Mellitus (either type 1 or 2) 6. Unstable medical condition. 7. Concomitant medication within 7 days prior to screening with drugs known to interfere with gastro-intestinal motility and sensitivity. 8. Pregnancy or breastfeeding. 9. Patient not able to understand or collaborate throughout the study. 10. Participation in other clinical trials in the previous 4 weeks.