 Xylitol is known to reduce counts of mutans streptococci ms as well as mother-child transmission of ms. Possibly xylitol delivered to infants could positively influence colonizationmetabolism of ms. By combining in a food supplement xylitol and B. lactis BB12 a well known probiotic bacteria we may be able to positively affect both gut and oral colonization, reflected in both dental and general health solid data available on the latter aim. Though B. lactis is in wide use in baby formulas and in in vitro tests it apparently is safe for the teeth, no clinical studies have looked at effects of its administration to infants on oral health. Our study aims to look at caries occurrence in infants who have received the xylitol BB12 food supplement with a pacifier. 