Saccharomyces boulardii is used for general GI problems, IBS, IBD, Crohn's disease, UC, Lyme disease, relapsing C. difficile, colitis, bacterial overgrowth, lactose intolerance, UTIs, vaginal and Candida-related yeast infections. It is the only probiotic, non-pathogenic yeast that survives gastric acidity, produces lactic acid and B vitamins, and treats and prevents diarrhea.