Our son toilet-trained beautifully at two and a half - we let him take the initiative and no problem. But now he's five and he's started holding back his number 2. He can hold it for many days, a week is the record so far. It drives us nuts. He has little accidents but refuses to sit on the toilet. We try not to get angry but we are really frustrated. He stinks, the laundry is disgusting, and our outings can become a real problem if he has an accident. When we ask him about it, he acts like it's no big deal. What's going on? Any ideas? The doctor recommended giving stickers or candies as a reward - no luck.I was amazed when I learned the answer to this problem, which is called encopresis. Believe it or not, the most probable cause is constipation! If a child has been constipated for long enough, his bowels are always full, so he can't sense when he needs to use the toilet.The problem begins when for some reason the child is unwilling or unable to defecate. If he has a particularly hard and painful stool, he may get a little crack or fissure which gives him pain when he uses the toilet. So he holds back his stool for as long as he can, because it hurts. After a while, the anal canal feels full all the time, so he always feels as though he has to "go," and he knows it always hurts if he does try to push the stool out. The stool becomes impacted and hard. Then, as he continues to eat and to produce more stool, it begins to leak out even though he doesn't push it out. Hence the encopresis - pooping in his pants.So the first and most important solution is a laxative, one suitable for children, to make the stool soft. Take time to explain to your son that the medication is to make the pooh soft so it won't hurt when it comes out, and let him talk to you about whether he's worried about it hurting. He may want to put some soothing cram around his anus to help heal any soreness, and to prevent new soreness once he starts to defecate regularly. Sit him on the toilet or a potty seat and read him a story once the laxative begins to work, at regular times, for a few minutes. Reward him when he produces, and if he isn't able to in about ten minutes, take him off and say you'll try again later. Ignore "accidents."Once the laxative makes him able to produce soft stool which doesn't hurt, explain to him that it's important to notice when he needs to "go," and go at once, so the pooh can't get hard and hurt him. Tell him to let you know if it hurts so you can help him with the problem. If you need more help than this column in following this regime, get your family doctor to refer you to a paediatrician. (I learned this method from one.)Occasionally there are other, more serious, emotional causes for encopresis. For example, children who are being sexually abused may dissociate their awareness from that area of the body, so they become unaware of any bodily sensations they need to pay attention to. If the above solution doesn't work, and a paediatrician has found nothing physical to account for the behavior, consult a psychologist. Encopresis which lingers for a long time can cause serious social problems with resultant loss of self-esteem.