Inclusion Criteria:  1. Male or female patients aged 18 to 75 years (inclusive); 2. Diagnosis of IBS according to ROME IV criteria (Appendix 3); 3. Abdominal pain score ≥ 4 on a 11-point NRS, on at least 2 days of the 14 days prior to the baseline visit and on at least 2 days of the last 14 days of the washout period, and pain score not > 8 in more than 7 days of each of the two above-mentioned periods; 4. Signed Informed Consent; 5. Patients' ability to comply with the study procedures; 6. Stable diet in the two months prior to the screening visit;  7. *Negative colonoscopy, defined as the absence of clinically relevant changes or of changes nonetheless relevant in relation to study participation risk, performed during the run-in period, unless:  a colonoscopy was performed within the previous 5 years and was negative as intended above, or, if more than one was performed within the previous 5 years, the last being negative as intended above; the symptoms, if any, for which the last colonoscopy was performed, have remained unchanged;  8. Postmenopausal female patients, i.e., females who have not had a menstrual period for at least 12 months or women who have undergone surgical sterilisation (tubal ligation or ovary removal). If not, women of childbearing potential must follow reliable contraceptive treatment.  Inclusion criteria applicable only for patients > 50 years of age  Exclusion Criteria:  1. Patients taking treatments that may significantly affect the efficacy outcomes measures, such as: probiotics and prebiotics (unless contained in milk-derived foods such as yogurt and cheese); drugs with adsorbent/sequestrant properties such as diosmectite; 5-HT3 receptor antagonist drugs, e.g. ondasetron; drugs that modify gastro-intestinal motility, e.g. "final" anti-cholinergic agents such as loperamide, or cholinergic agents; laxatives and faecal softeners) unless they have been taken at a stable dose for at least four weeks prior to the screening visit. 2. Patients taking tricyclic antidepressants within six months prior to the screening visit; 3. Patients taking opioid-containing analgesics within one month prior to the screening visit; 4. Patients taking antibiotics within one month prior to the screening visit; 5. Patients with relevant organic, systemic or metabolic disease, or laboratory changes, that are deemed significant based on specific ranges of normality; 6. Patients with organic bowel diseases; 7. Patients with unstable psychiatric conditions; 8. Patients who have undergone major abdominal surgery, except appendectomy; 9. Known hypersensitivity to one or more of the components of the products. 10.Women with known or planned pregnancy or breastfeeding; 11.Patients with malignancies of any type, or with a history of prior malignancies, except for patients with a history of extra-intestinal malignancies that have been surgically removed and have not relapsed within the five years prior to participation.