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Study of Saccharomyces boulardii CNCM I-745 to treat symptoms in adults with non-constipated Irritable Bowel Syndrome

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on Irritable Bowel Syndrome (IBS), specifically the non-constipated type, which is a disorder affecting the digestive system that can cause stomach pain, bloating, and changes in bowel habits. The study will test a treatment called Saccharomyces boulardii CNCM I-745, which is a type of beneficial yeast, comparing it with a placebo. Another medication called loperamide may be used during the study to help manage symptoms.

The purpose of this research is to determine if Saccharomyces boulardii CNCM I-745 can improve overall IBS symptoms when taken over an 8-week period. The treatment will be given in the form of hard capsules that are taken by mouth. The study will measure how the treatment affects various aspects of the condition, including stomach pain, bloating, and overall quality of life.

During the study, participants will take either the treatment or placebo for 12 weeks. The researchers will monitor any changes in symptoms throughout this period and continue observations for some time after the treatment ends. They will also keep track of any side effects that might occur during the study period. The study is designed so that neither the participants nor the doctors know who is receiving the actual treatment or the placebo until the study is complete.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment and medication start

    Your participation begins with an evaluation of Irritable Bowel Syndrome (IBS) symptoms using a special assessment scale called IBS-SSS

    You will receive either Saccharomyces boulardii CNCM I-745 capsules or placebo capsules for oral use

    You will be asked to maintain your regular nutrition habits throughout the study period

  2. Step 2

    First follow-up (Day 28)

    Your IBS symptoms will be evaluated again using the IBS-SSS scale

    Your response to the treatment will be assessed

    Your vital signs and body weight will be measured

  3. Step 3

    Main evaluation (Day 56)

    A comprehensive evaluation of your symptoms will be conducted using the IBS-SSS scale

    Your quality of life will be assessed using a specific questionnaire

    Your response to the treatment will be evaluated, including changes in abdominal pain

    Your vital signs and body weight will be checked

  4. Step 4

    Final assessment (Day 84)

    Final evaluation of your IBS symptoms using the IBS-SSS scale

    Final quality of life assessment

    Final measurement of vital signs and body weight

    Overall evaluation of your response to the treatment

    Review of any side effects or health changes experienced during the study

Who can join the trial?

7 criteria

  • Age between 18 and 65 years (both men and women can participate)
  • Must have been diagnosed with Irritable Bowel Syndrome (IBS), but not the constipation-predominant type
  • Must have a severity score of 175 or higher on the IBS Symptom Severity Scale (a tool used to measure how severe IBS symptoms are)
  • Must be willing and able to maintain current eating habits throughout the study period
  • Must be able to understand and follow study requirements
  • Must be willing to provide written informed consent (formal agreement to participate)
  • For women who can become pregnant: must agree to use effective birth control methods during the study

Who cannot join the trial?

13 criteria

  • Known allergy or hypersensitivity to yeast or any ingredients in the study medication
  • Currently taking antifungal medications (medicines that treat fungal infections)
  • History of inflammatory bowel disease (chronic inflammation of digestive tract) such as Crohn's disease or ulcerative colitis
  • Current diagnosis of celiac disease (condition where gluten damages the small intestine)
  • History of gastrointestinal surgery in the past 6 months (except for appendectomy or gallbladder removal)
  • Current severe constipation (having less than 3 bowel movements per week)
  • Active gastrointestinal infection or food poisoning in the past 4 weeks
  • Current use of probiotics (beneficial bacteria supplements) within the last 2 weeks
  • Pregnant women or women planning pregnancy during the study period
  • Breastfeeding women
  • Current participation in other clinical trials
  • Severe mental health conditions that could affect study participation
  • Inability to follow study procedures or complete required questionnaires
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Investigated drugs

Saccharomyces boulardii CNCM I-745 is a beneficial yeast that is used as a probiotic medication. It helps manage symptoms of Irritable Bowel Syndrome (IBS) in adults who do not have constipation. This probiotic works by supporting gut health and may help reduce various digestive symptoms associated with IBS, such as abdominal discomfort, bloating, and irregular bowel movements. The medication is being studied to evaluate how well it improves overall IBS symptoms compared to a placebo.

What is already known about the treatment

Saccharomyces boulardii CNCM I-745 - A probiotic yeast strain administered orally in capsule form, widely studied and used in modern medicine for gastrointestinal disorders. This beneficial microorganism works by improving gut microbiota balance, strengthening the intestinal barrier, and reducing inflammation in the digestive system, making it particularly effective for treating Irritable Bowel Syndrome (IBS) symptoms. It belongs to the pharmacological class of probiotics and has shown promising results in clinical trials for managing non-constipated IBS, with a well-documented safety profile in medical literature.

Investigated diseases

Irritable Bowel Syndrome (IBS) - A chronic gastrointestinal disorder that affects the large intestine. IBS involves changes in the patterns of bowel movements and causes recurring abdominal discomfort. The non-constipated type is characterized by loose stools, diarrhea, bloating, and abdominal pain or cramping. Symptoms often come and go in periods of flare-ups and remissions. The condition typically involves heightened sensitivity of the digestive system to various triggers, including certain foods, stress, or hormonal changes.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-520276-10-00Protocol codeBoWell - Sb252Estimated enrolment365 patientsSponsorBiocodex

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