hello i have gone through your query. Constipation and hard stool in a child can be caused by: not eating enough fibre not drinking enough fluids drinking too much milk and not enough water lack of exercise and activity being anxious about Toilet(potty) training diet including cow s milk, bananas, yogurt, cheese, cooked carrots and other foods that are low in fiber sud be adviced soy milk is a good alternative, as it is usually much less constipating than cow s milk. Another important dietary change is increasing the amount of fiber in your child s diet.foods such as wholemeal bread and cereal, and fruits and vegetables such as prunes, figs, plums, peas, broccoli, sweetcorn, potatoes and baked beans can be given Give your child plenty of fluids to help moisten his stool. some cases a laxative like lactulose (laxil) is advised by a doctor to soften the stool, but the main thing is to the follow the above instructions first. if the problem persists you sud visit a doctor Hope this ans helps Regards Dr. Shesh