The purpose of the study is to monitor safety and to evaluate the efficacy of a probiotic formulation on abdominal pain, abnormal defecation, comorbid mood disorders (anxiety and depression) as well as general quality of life in adults with IBS-D.

To monitor safety and to evaluate the efficacy of a probiotic formulation on severity of gastrointestinal symptoms (abdominal pain, abnormal defecation), anxiety, depression and quality of life in adult participants with IBS-D.

Inclusion Criteria:

• Experiencing symptoms of IBS-D
• Having a diagnosis of IBS-D based on Rome IV criteria
• Participants with symptom onset at least 6 months before diagnosis
• Having a normal colonoscopy result in their medical file

Exclusion Criteria:

• A history of inflammatory or immune-mediated gastrointestinal diseases
• Diagnosed with a co-existing organic gastrointestinal disease which can affect the study
• Currently undergoing a treatment for other severe conditions such as coronary disease, neurological disorder, kidney or liver disease,
• Currently diagnosed with an eating disorder,
• Having undergone any abdominal surgery including cholecystectomy, with the exception of hernia repair or appendectomy
• Currently diagnosed with any mood- or anxiety-related disorder, major psychiatric illness, or participants with a history of suicidal ideation, or current suicidal ideation,
• Regular use of anti-diarrhea medications and laxatives however occasional use is permitted (≤ than once a month); if current use is > once per month a one month wash out is needed,
• Unwilling to avoid the use of antidiarrheal or laxative medication on an "as-needed basis" during the full length of the study,
• Pregnant, breast-feeding or planning on becoming pregnant.

After publications of the results, de-identified data will be shared with qualified researchers and scientists upon reasonable request to the sponsor including a detailed proposal of the intended use of the data, as per the Lallemand Health Solutions Inc. Policy on Clinical Trial Transparency and Data Sharing (available upon request).