Shown in over 50 years of extensive international use to be studied and trusted* According to the World Health Organization, probiotics are "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host." Florastor contains the active ingredient, Saccharomyces boulardii lyo, a non-pathogenic yeast found naturally on the skin of tropical fruit (lychee and mangosteens). Florastor keeps your intestines functioning well. Florastor also acts to maintain the balance of intestinal flora.* Long-term use of Florastor is not associated with complications. After repeated oral doses, Florastor transits through the digestive tract attaining steady-state levels that are maintained throughout the administration period. Florastor is no longer present in stools two to five days after discontinuation of treatment. *These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.