Constipation is one of the most common medical problems in the childhood period. Several therapeutic regimes are available in management of constipation, but still considerable numbers of patient have not shown enough response to these modalities. In this challenging situation, physician should pay enough attention to important aspects of this disease and review each one carefully. In this article, we have described the three major confounding cause of hard to treat constipation. The first one is incorrect diagnosis although The most common causes of constipation in children are Hirschsprung's disease and functional constipation, less common causes like anal problems, abnormal neuromuscular condition, pseudo-obstruction, spinal cord abnormalities, drugs side effects, electrolyte and endocrine abnormalities should be considered in these patients. The second cause is incomplete adherence of both patient and parents to recommended therapeutic regime and the third important point is inadequate therapeutic modality. There are several drugs prescribed for constipation, but the most preferred medication is Polyethylene Glycol: PEG, the dose of drugs should be increased as need to induce tow soft defecation per day, and then reduce the dose of drug gradually during months. Drugs with unacceptable side effects like bloating, abdominal pain, vomiting or have unpalatable taste should not be prescribed for long lasting use and may lead to treatment failure.