This study is being done to assess the effects of S. boulardii CNCM I-745 compared to placebo on impaired intestinal permeability, which is the control of material passing from inside the gastrointestinal tract through the cells lining the gut wall into the rest of the body.

This placebo-controlled parallel group clinical study in healthy adults from the general population aims to investigate whether oral supplementation with S. boulardii CNCM I-745 could strengthen the intestinal barrier function and counteract the acute NSAID-induced hyperpermeability. Indomethacin will be used short term to increase intestinal permeability. The primary objective of the study is to assess the effects of S. boulardii CNCM I-745 on this impaired intestinal permeability.

Inclusion Criteria:

• Considered as healthy after a comprehensive clinical assessment (detailed medical history and complete physical examination).

• With a body mass index (BMI) comprised between 18 and 35 kg/m^2 and weight > 50 kg at Screening.

• Able to comply with study requirements and to provide signed informed consent.

• Has signed the informed consent form before beginning any study procedure.

• Regular defecation (frequency and stool consistency, with at least about three bowel movements a week).

• For women of childbearing potential:

  • A negative urine pregnancy test immediately prior to starting the study treatment;
  • Agreement to comply with approved methods of contraception during the whole study: unless they meet the criteria of post-menopausal; i.e., 12 months of spontaneous amenorrhea, women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, including women whose career, lifestyle, or sexual orientation precludes intercourse with a male partner, should use one or more of the following acceptable methods of contraception that should be maintained throughout the study:
  • Surgical sterilization;
  • Hormonal contraception (implantable, patch, oral, intra-muscular);
  • Intra-uterine device;
  • Double barrier method (diaphragm plus condom);
  • At the discretion of the investigator, total abstinence is acceptable in cases where age, career, lifestyle, or sexual orientation of the patient ensures compliance.

Exclusion Criteria:

• History of hypersensitivity to the study treatments (active substance or excipients), brewer's or baker's yeast.
• Contraindication and special warning to the study treatments according to the Summary of Product Characteristics (SmPCs).
• History of chronic constipation with passage of fewer than 3 spontaneous bowel movements per week on average.
• History of chronic or recurrent diarrhea with spontaneous unformed bowel movements equivalent to or more often than 3 times daily.
• Prior gastrointestinal surgery (apart from appendectomy or cholecystectomy performed at least more than one year ago).
• History of Clostridium difficile infection.
• Active gastrointestinal disease.
• Known chronic or recurrent systemic disorder (including diabetes and hypertension) that may interfere with the study treatment evaluation.
• Associated immune deficiency.
• Severe hepatic or renal impairment.
• Clinically relevant abnormalities in results of laboratory tests as per Investigator's judgement.
• Patients with a central venous catheter.
• Oral or systemic antibacterial therapy during the 3 months prior to study enrollment.
• NSAIDs and proton pump inhibitor treatment longer than 1 week, within 3 months prior to study enrollment.
• Steroids within 6 weeks prior to study enrollment.
• Use of medications affecting gastrointestinal transit or permeability within 7 days prior to the testing.
• Use of artificial sweeteners, lactulose, mannitol within 2 days prior to the testing and during the 24 h testing period.
• New prescription medications during the 2 weeks prior to study enrollment.
• Use of probiotics or drugs that alters gut microbiota or function, during 4 weeks prior to study enrollment.
• Intake of antifungals within 14 days prior to study enrollment.
• Substantial changes in eating habits within 30 days prior to receiving the first dose of IMP product, as assessed by the Investigator.
• Current smoker.
• History or presence of drug or alcohol abuse.
• Inability to abstain from intensive muscular effort the day before the intestinal permeability test.
• Breast-feeding woman.
• Patients enrolled in another clinical trial within the past 30 days.
• Patients not able to fill in the study questionnaires.
• Any condition or personal circumstance that, in the opinion of the investigator, renders the subject unlikely or unable to comply with the full study protocol.