Nightmares can be frightening experiences for everyone, but for children who haven't learned to distinguish reality from fantasy, they can be especially disturbing.
Nightmares are most common when the child goes to bed in a state of anxiety or stress.
It might be an indication that they have an unresolved issue bothering them about school or home. If your child wakes from a nightmare, go to them quickly. Often, the child will fall back to sleep if you simply sit beside them and talk in a soothing voice. It is important to comfort them. It usually isn't necessary to turn on the light or to make the child talk about the dream unless they want to.