Constipation is generally not a serious problem. But it can make the child uncomfortable. Causes Adding new foods, such as chocolate, to your child's diet can cause constipation. Eating or drinking too much milk, cheese, yogurt, ice cream, or other milk products can cause the problem. Certain medicines, such as iron, also can cause constipation.
Constipation can also result from waiting too long to go to the bathroom.
School-age children can become constipated because they are afraid of using the school bathroom. Family problems such as a new baby or a family death also can cause some children who are being toilet trained to become constipated. Your child may cry while trying to pass the movement or say that it hurts. The child may go many days without having a bowel movement. He or she may want to have one, but even with pushing and straining, can't pass the stool.