Evidences of some probiotics' positive effects in the treatment of diarrhea are abundant, especially those regarding lactobacillus rhamnosus and saccharomyces boulardii. Indeed, as professor Farinelli (University of Perugia) underlines, these two strains have been currently inserted in ESPGHAN guidelines fot the treatment of diarrhea. The positive effects of probiotics is also demontrated by the reduction of at least one day of the lenghth of hospitalization.