Antibiotic use, daily stresses, poor diets, chemicals, age, fluoride exposure, etc. makes the digestive system susceptible to pathogenic bacteria and yeast overgrowth. RestorFlora is formulated with Bacillus Subtilis HU58 and Bacillus Clausii; both species have been shown to be potent competitive exclusions probiotics and widely used as a protective probiotic for nearly 60 years in the pharmaceutical industry in Europe and Asia.