Your baby's been long predisposed to liking sweet flavors (he's been able to taste since his days in the womb), so adding sweet flavorings like cherry or grape to medicine can help your baby swallow it more readily. In fact, research shows that newborns will make happy faces when they taste a sweet solution and grimace at sour and bitter ones, although they don't react to salt until about 4 months old. Young babies will put up with almost any flavor (because they don't seem to realize that sucking brings the bad taste to their mouths), but older ones will indeed swallow sweet medicine more easily. Looks like Mary Poppins' adage about a spoonful of sugar is sound.
Originally published in Child magazine.