How can I make my preschooler stop biting?
For starters, do what you did when your child was a toddler: Tell her firmly that biting is wrong, give her a time-out to reinforce the lesson, and try to head off the hunger, fatigue, or frustration that loosens her self-control so she's more likely to behave badly. But go one step further: Your preschooler is much more verbal than she was as a toddler, and she has a better understanding of past, present, and future. That means you can discuss biting with her not only when she does it but before she tries it again.
   
Role-playing can help your child find alternatives to biting in stressful situations. If you often go to a park where several children want a turn on the swing, act out the scene with your child before your next visit. You can play the kid who refuses to share. What should your child do: Bite you, or get an adult to help? What if your child gets tired? Come up with a special

word she can use to tell you she's had enough.
   
Remind your child to "talk it out" when she feels angry or frustrated. When she gets agitated, have her stop what she's doing and calm down. Take her to a quiet place if necessary. Gently tell her that she must use words so that you can understand and help. Reward her efforts to communicate by responding positively ("Oh, now I understand: You want to use the swing! Let's go ask that girl's mother to help"). Your child should learn that words get results, while biting or whining gets her nowhere.

Is biting normal at this age?
Yes, though you should help your child to stop as soon as possible. Children bite less frequently as they grow older, but biting is common in situations where children are thrown together such as daycare and play groups. Many young kids lack the verbal skills to deal with conflict and their own strong emotions.

Why does my child bite?
Like a temper tantrum, biting is easy and gets instant results. And practically every kid has seen someone else do it. But there are two other reasons that children of this age bite.
  
The first is physical fear: Typically, a preschooler is in a fight and feels that she's cornered or about to be hurt. If a bite occurs during a tussle with another child, make sure your child understands that biting is unacceptable -- and so are hitting, punching, and kicking. Take the opportunity to talk about how she might better respond in the future if she feels threatened.
 
The second is frustration, anger, or other intense feelings. A major change, such as a new baby in the family or a new home, can cause emotional upset that results in aggressive behavior. Work with your child to learn why she bites, then address her needs, whether for reassurance or ways to express her emotions.

Can my child's daycare provider or teacher help her stop biting?
Yes. These adults are in a perfect position to observe your child's behavior and give you tips on why she's biting. They can also work with all the kids on resolving conflicts without becoming aggressive.
  
Schedule a meeting with your child's teacher or daycare provider. Ask how she deals with children's disagreements. Does the program have an established approach to conflict resolution? Is all aggressive behavior prohibited, whether it's biting, punching, or constant teasing? Are children praised for good behavior, or is your child's biting the only way she can get attention? Does the program director or teacher talk with the whole group about topics such as sharing toys peacefully? A daycare center or preschool should have firm rules on aggressive behavior and be making an ongoing effort to teach all of the children how to resolve their differences amicably.