Weaning: What, When, and How

12 to 18 Months: Stop Thumb Sucking

The thumb is beloved for several reasons: It's soothing, it satisfies Baby's need to suck, and it's available 24/7. But such easy access also makes it harder to give up. Trouble is, prolonged thumb-sucking can affect the alignment of your child's teeth, pushing them forward or apart. Thumb-suckers can also develop a callus that might become infected; thumbnail infections are quite common too. As if that weren't enough motivation to help your honeybun quit, children who frequently put their fingers in their mouth have an increased risk for pinworms, an intestinal parasite.

Between 12 and 18 months is an ideal time to put the kibosh on thumb-sucking, Dr. Greene says. There's been no permanent damage to teeth yet, and this time frame coincides with the period when most kids start to take their first steps, which makes for a terrific distraction. Toddlers often wear themselves out practicing this new skill; come bedtime, they're too tired to suck.

Break the Habit Around 1 year, your child no longer has that strong need to suck. But he'll often pop in his thumb out of boredom. Gently take it out, and then distract him with a toy that he needs both hands to play with. "You can also try dipping his thumb in vegetable juice during the day to deter any sucking," Dr. Greene recommends. At night, apply a small amount of bitter-tasting (but completely safe) nail polish to his thumbs, such as Mavala Stop ($11; Amazon.com).

Yes! Weaning Success! "We thought up the 'thumb fairy,' who shows up only when my daughter's thumb is not in her mouth. She'd get so excited that she started taking her thumb out before she went to sleep so the thumb fairy would pay a visit, and then she finally stopped sucking altogether," says Cory Kingston, of Manhattan Beach, California.