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This article originally appeared in the Feb. 24, 2011, edition of the St. Louis Post-Dispatch. 

Does your child bite his or her fingernails? Some children and adults do this, especially when they are feeling nervous, but it's definitely not a healthy habit and it’s one you can help your child break.

Our fingernails have a couple of important functions. They protect our fingertips and make it easier for us to pick up tiny things, like loose threads. They also come in handy when you have an itch that needs scratching.

Parents should explain to their children that when nails are bitten, they aren't there to do those things. Also, and more importantly, nail-biting leads to breaking the skin and possibly allowing germs into these openings in the skin. You might also touch on the social aspects of bitten nails – no one likes to look at fingers with ragged nails or bleeding nail beds.

Speaking of germs, there are germs under fingernails, so when your child bites them, those germs can go into their mouth. It might be helpful to remind your child of all the germy and downright icky things they touch all day long, like their baby sister's drool-dripping pacifier, their stinky gym socks, or slimy earthworms for their science project. Most kids would agree that they don't want those nasty germs getting in their mouths.

If reasoning with your child doesn’t work, consider the benefits of positive reinforcement, advises pediatrician Ken Haller, M.D.

“Try saying something like ‘I notice you haven’t bitten your nails in hours. I am so proud of you!’ to your child,” says Haller, who is a pediatrician at Cardinal Glennon Children’s Medical Center and associate professor of pediatrics at Saint Louis University . “This repeated positive reinforcement over a period of time can help to kick the bad habit.”

Because nail biting is a habit, your child may not realize he is doing it. After talking with your child about the good reasons to stop, you might offer to gently remind them if you notice them biting their nails. If sheer willpower isn't getting them anywhere, some parents find success in using a special colorless nail polish that makes fingernails taste bad. This can help your child learn to stop biting.

Like smoking is for adults, nail biting can be an addictive habit for children. Help your child kick the habit with love, encouragement and positive reinforcement.

Dr. Bob Wilmott is Chief of Pediatrics at SSM Cardinal Glennon Children’s Medical Center and is a Professor of Pediatric Medicine at Saint Louis University School of Medicine. If you have a question about your child’s health, go to the “Ask Dr. Bob” section of the Cardinal Glennon Web site at


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