Constipation is a common problem among children. The majority of children suffering from constipation have no underlying disease. Although constipation has no basis in underlying disease, it often leads to a reduced quality of life of children who are on par with or worse than for children suffering from serious diseases such as cardiovascular and rheumatic diseases.

Despite the high frequency of constipation among children, little is known about the causes and treatment of constipation.

Treatment consists of symptomatic treatment with various laxatives. Movicol and Movicol junior has proven very effective and are therefore widely used in children as disimpaction and maintenance treatment. There is currently no research to prove the need for and length of maintenance treatment with laxative medications in children.

The purpose is to examining the effectiveness of maintenance treatment with Movicol. Additional til study will examine how the anal diameter change during a course of treatment and the degree to which it can be used as an indicator of treatment efficacy.

The study will test the following:

• What is the effect of maintenance treatment with PEG compared to placebo?

The results from this study are expected to form the basis for an evidence-based approach to the use of maintenance therapy and the use of ultrasound of the rectum in children with constipation.

Inclusion Criteria:

• Children between 2 and 16 years and referral to our out patient clinic with either constipation or fecal incontinence.
• Patients must fulfill the Rome III criteria of constipation, which mean they must have at least 2 of the following characteristics: fewer than 3 bowel movements weekly, more than 1 episode of fecal incontinence weekly, large stools in the rectum by digital rectal examination or palpable on abdominal examination, occasional passing of large stools, display of retentive posturing and withholding behavior, and painful defecation.

Exclusion Criteria:

• Children with known organic causes of constipation, including Hirsprung disease, spinal and anal congenital abnormalities, previous surgery on the colon, inflammatory bowel disease, allergy and metabolic or endocrine diseases.
• Children receiving drugs known to affect bowel function during a 2 month period before initiation.
• The healthy control group consists of children with no history of constipation (Rome III), urinary incontinence, urinary tract infections, fecal incontinence, laxative use or any other disease affecting the digestive system.
• Children receiving medications known to affect bowel function are excluded from the study.