Every toddler has bit or has been bitten but if you have a child that has bit it dosn't mean that they are a biter. There have been studies that were done that show about half of children attending daycares have been bitten three times per year. So toddlers biting is in fact a very common thing.
Biting can come in different stages. The first stage is when the teeth are erupting from the gums. This is when your toddler will bite to make their gums feel better. This should be done on a rattle or a teething ring. If your baby tries to bite you while breast feeding quickly remove the infant and set them down in a safe place. When an infant gets a negative response from their mother they will soon stop biting.
About the time that your toddler has their first birthday is when they have their second stage of biting. They usualy bite to show some excitement. At this time when your toddler tries to bit you should respond firmly every time and it should stop almost immediately.
Again your toddler may start to bite around the age of two. Your toddler bites at this time to show that they want to be independent. When your toddler bites to prove that they are in control then you need to give the child a time out and explain that it hurts. Teach your toddler commutation skills that they may be lacking. After your toddler has the skills that are needed to commutate the biting should stop.
If your toddler is going through a biting stage make certain that you closely watch them. The best thing to do at this stage is to acknowledge the good behaviour. It wouldn't hurt to offer your toddler something to chew on at this stage either. If you catch your toddler biting you need to immediately respond with a firm toned voice and put your toddler on a time out.