I've heard babies referred to as veritable drool machines, a description that's not far from the truth. It seems there's always something coming out of a baby's mouth—drool, spit-up, half-chewed bananas. While this is a boon for companies that make baby bibs, it's annoying for the fastidious parent. (Moral: Don't be fastidious.)
Typically, a baby begins to drool when tooth buds under the gums erupt into teeth. (If you run a finger along the gum line, you can usually feel the bumps of new teeth growing just under the surface.) Whenever something—new teeth, his fist, the car keys—is in an infant's mouth (a friend calls her baby's mouth his third hand), he produces excess saliva. Adults swallow their excess saliva, but most babies don't. Until he's around 6 months, about the same time the first tooth shows up, a baby will have a hard time getting the saliva that's in the front of his mouth to the back to be swallowed. Instead, he drools.
Did You Know?
Saliva aids in digestion, especially for infants. Because an infant's pancreas won't reach full digestive capacity for several months, an enzyme in her saliva breaks down the fat in milk or formula until the pancreas is up and running.
Adapted with permission from Why Babies Do That: Baffling Baby Behavior Explained, by Jennifer Margulis, published by Willow Creek Press. 2005 by Jennifer Margulis. All rights reserved.