Saccharomyces boulardii is a nonpathogenic, transient yeast long used to support normal bowel transit time.* It is a hardy, acid-resistant, temperature tolerant species. S. boulardii is genetically and functionally distinct from brewer's yeast (S. cerevisiae) and different from pathogenic Candida species. Klaire Labs S. Boulardii is American Type Culture Collection (ATCC) certified and freeze-dried to maintain maximum strength and viability. Klaire uses only lactose-free, gluten-free material. Clinical effectiveness of probiotic organisms is dependent on many variables. Identification and selection of appropriate, documented probiotic species as well as maintenance of maximum viability throughout all stages of handling is central to expression of the full potential of beneficial gut flora. Klaire Labs probiotic quality assurance commitment includes a rigorous independent testing program that monitors and ensures the identity, viability, and hypoallergenicity of raw materials and finished products.