Children with intestinal failure have a lack of tolerance for food in the intestine. The children are dependent on intravenous nutrition over a long period of time period to ensure growth and development. The condition is characterized by bacterial overgrowth in the intestine, with nausea, vomiting, diarrhea and flatulence as physical symptoms. Mental health is affected in the form of lower quality of life, lack of school participation and less social contact with peers. The investigators own (unpublished) data show that children with intestinal failure have a lower quality of life than healthy people. Standard treatment is antibiotics, but the effect of these is short-lived, and many must have repeated courses. Prebiotics are indigestible carbohydrates (fiber) in foods that positively affect the bacterial flora and promote intestinal health. In this project the investigators want to see if supply of prebiotics can change the bacterial balance, reduce symptoms of bacterial overgrowth and increase quality of life. The study is unique, as Prebiotics have not previously been used in the treatment of intestinal failure. If successful, it can pave the way for a new and better treatment method that can potentially be transferred to other conditions with imbalance in the intestinal flora. The study is a randomized intervention study and is consist of two phases. In phase 1, the effect of 4 weeks of open intervention with prebiotics is studied to establish so-called "proof of concept". Data from phase 1 are used to look at connections between the composition of intestinal flora, nutritional status and bowel function. The intervention involves the use of a prebiotic product (Stimulance, Nutricia), which is added to childs regular food. In phase 2, patients are randomized into two groups. One group will continue with the product for 6 months, while the other group does not receive prebiotics.

Quality of life, gastrointestinal symptoms and family impact are measured using validated forms for four weeks before intervention phase 1, at start-up and after phase 1, as well as after phase 2. Stool samples are collected at the same time points. Weight, height is measured and blood tests are collected at the start and end of phases 1 and 2. Data on diet and nutritional treatment are collected at the start and end of the two phases. The stool samples are analyzed for short fatty acids (marker for good intestinal health), the composition of the intestinal flora and inflammation markers. Blood samples are analyzed for infection markers, intestinal health markers and nutritional markers. Nutritional data are analyzed for nutrient content and the dependence on nutritional support is calculated.

The investigators expect that the study will lead to an improved quality of life for the patient group through increased tolerance to food in the intestine, reduced antibiotic use and reduction of gastrointestinal symptoms. The project is patient-oriented.

Inclusion criteria are:

• Diagnosed with congenital malformations or diseases requiring intestinal surgery leading to short bowel syndrome or
• Diagnosed with conditions and diseases leading to intestinal failure e.g pseudo obstruction.

And Treated with parenteral nutrition for minimum 60 days within a 74 day period.

Exclusion criteria:

• Children in need of temporary advanced nutrition intervention due to illness, e.g. infections.
• Children with temporary malfunctioning gut due to advanced medical treatment, for example cancer treatment or transplantation