In case of ineffectiveness the dose of medication will be increased every two weeks with 0.2 g/kg. The indication for the increase in dose will be less than 3 bowel movements per week. For children with diarrhea defined as more than 3 loose stools for minimum 2 days or/and severe abdominal pain the macrogol dose of will be reduced every two weeks by 0.2 g/kg. The intervention will last 6 weeks.