Chronic functional constipation is a common disorder in childhood. The treatment most often consists of the modalities education, disimpaction and maintenance. In a recent Cochrane review of maintenance treatment polyethylene glycol (PEG) seems to be superior to placebo and to other laxatives including lactulose. This conclusion is in line with practice at most paediatric departments in Denmark. Still, larger randomized controlled studies with the curing of constipation as the primary end point are needed.