This randomized study evaluates the usefulness of the I31 probiotic formula, alone or in combination with alverine/simethicone, against placebo, in the treatment of diarrhea-predominant or mixed irritable bowel syndrome

Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disease in which recurrent abdominal pain is associated with defecation or a change in bowel habits. Disordered bowel habits are typically present (ie, constipation, diarrhea, or a mix of constipation and diarrhea), as are symptoms of abdominal bloating/distention.

I31 is a probiotic formula composed of strains Pediococcus acidilactici CECT7483 and Lactobacillus plantarum CECT7484 and CECT7485, previously shown to improve quality of life in patients with IBS of Caucasian descent.

Alverine/simethicone is a combination of two drugs: Alverine citrate relaxes muscle cramps that occur in the intestine in conditions such as irritable bowel syndrome and diverticulosis. Simethicone is an antifoam administered orally. Reduces gas formation and facilitates its elimination from the digestive tract

Inclusion Criteria:

• Subjects attending Hospital Juarez de Mexico with a diagnosis of diarrhea-predominant or mixed irritable bowel syndrome (IBS-D and IBS-M), according to Rome-IV criteria (Lacy et al. Gastroenterology 2016), providing Informed Consent.

Exclusion Criteria:

• Unexplained weight loss, blood in feces, anemia.
• Use of systemic antibiotics, NSAIDs, antipsychotic or prokinetic medication in the 3 weeks before study initiation.
• Pregnant or lactating women.
• History of gastrointestinal cancer.
• Suspicion of coeliac disease, inflammatory bowel disease (IBD), endometriosis or pelvic inflammatory disease.
• History of abdominal surgery within 2 years (3 months if appendectomy or herniorraphy)
• BMI below 18
• Known allergy to any of the components in the treatments