Effects of S. Boulardii and Amoxicillin/Clavulanate on Gut Microbiota

Inclusion Criteria: * Age 18 to 65 years (male or female) * Good general health * Able to comply with study requirements and to provide informed consent * For women of childbearing potential oA negative urine pregnancy test immediately prior to starting the study treatment oAgreement to comply with approved methods of contraception during the period of active study treatment (not required during follow-up) Exclusion Criteria: * History of organ transplantation * Known chronic or recurrent systemic disorder associated with immunocompromise * A history of allergy or hypersensitivity to Saccharomyces boulardii, brewer's or baker's yeast, amoxicillin, penicillins, or cephalosporins * History of severe allergic reaction (requiring hospital admission and/or the administration of parenteral medication or associated with dyspnoea, wheezing, hypotension, loss of consciousness). * Oral or systemic antibacterial therapy during the 3 months prior to study enrollment * New prescription medications during the 4 weeks prior to study enrollment * Prescription, OTC medications or supplements that are known to alter gut function or microflora (i.e. acid antisecretory drugs, probiotics) during the 4 weeks prior to study enrollment * Active gastrointestinal disease * Patients with a central venous catheter * Patients taking antifungals or laxatives within 14 days of enrolment * Patients enrolled in other clinical trials within the past 60 days * Prior gastrointestinal surgery (apart from appendectomy or cholecystectomy) * History of chronic constipation with passage of fewer than 3 bowel movements per week on average * 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.