Tooth decay is an infectious disease, and it is usually the mother who infects her own baby. Germs are passed between a parent’s mouth and the baby’s mouth. Germs are given to the baby in saliva by kissing, “cleaning” a pacifier, tasting food on a spoon, and so on. Regular consumption of xylitol can prevent transmission of cavity-causing bacteria from a mother to a child. Parents who consume two teaspoons of xylitol every day will gradually clean away unhealthy bacteria from their own mouths. If this program starts at least six months before the baby has a tooth, parents can avoid passing along unhealthy mouth bacteria to the baby.