What's the most effective way to prevent constipation in children?

Water: Ensure they are taking plenty of fluids, fresh vegetables, fruits, and fiber in the form of cereals and multigrain breads. A good rule of thumb is one ounce of water for every pound of body weight every day.

No simple answer: Movement of stool through the colon requires some basic elements. The stool must be of appropriate consistency to move easily, not too stiff or hard. The colon must have coordinated and effective motility - the ability to move to stool along the bowel. And there must not be any areas of excessive resistance to movement of the stool - such as strictures or non-relaxing anus.