• Nail chewing is a habit that can persist through childhood.Jupiterimages/Photos.com/Getty Images
  
  Chewing and biting nails is a habit that many children pick up early in life. According to Kid's Health, "30% to 60% of kids and teens chew on one or more fingernails." There are several tricks and techniques to help children break this habit. If one doesn't work, try another until you find the solution that works for your child.
  
  

Reduce Stress

• Nail biting may result from anxiety or stress or in your child's life. Examine your child's daily life and try to address any issues, challenges or experiences that may be causing stress in your child's life. These issues may include bullying, fighting parents, body issues or more. It may be necessary to seek the counsel of a health professional to help you deal with these problems.
  
  

Reward Good Behavior

• Children respond more favorably to praise than to punishment, so rather than scolding your child for his bad behavior, reward his good behavior. When you notice that your child is not chewing his nails, comment, praise and dote on him. Once you notice he has returned to nail chewing, ignore the activity. He will hopefully recognize that good behavior is more enjoyable than bad.
  
  

Nail Polish

• Nail polish can be used in two ways. First, you can paint your child's nails a pretty color so that she is discouraged from ruining her manicure. This associates nail biting with unsightly hands and is more effective for older girls. Second, paint your child's fingernails with an over-the-counter deterrent polish. The taste of these polishes is off-putting and discourages your child from biting their nails.