Vivatlac in Irritable Bowel Syndrome II (ViIBS2)

Inclusion Criteria: * diagnosed for Irritable Bowel Syndrome using the IBS questionnaire for Health Care Providers of the World Global Gastroenterology Organization * IBS-SSS ≥ 175 points Exclusion Criteria: * patients currently taking products containing probiotics or have taken this kind of products during the last 3 months * patients currently taking antibiotics or have taken antibiotics during the last 3 months * patients having a concurrent severe illness (malignancies, uncontrolled hypertension or diabetes, hepatic, renal or cardiac dysfunctions, serious neurological disorders, psychosis, respiratory disorders such as asthma or COPD, hyper- or hypothyroidism * patients having chronic bowel disorders other than IBS, including inflammatory bowel disease, gastroenteritis, stomach and duodenal cancer, celiac disease * patient being pregnant, lactating, or planning to become pregnant during the next 9 months * patient being diagnosed to have a lactose intolerance * patients using motility drugs or dietary fiber supplements withing 2 weeks before study start * patient taking anti-coagulant medication * patients have participated in another clinical trial within the last three months