Inclusion Criteria:
1. Male or female patients, ages 2 years to 18 years, inclusive.
2. Diagnosed with SBS, as determined by medical history and PN dependence (i.e. need for PN for \>60 days after intestinal resection or a bowel length \<25% of expected).
3. Congenital or acquired gastrointestinal disease requiring surgical intervention that has occurred at least 3 months prior to screening.
4. Patient is on parenteral lipid and at least 30% of daily caloric and fluid intake has been provided by PN for a least 6 months prior to screening
5. Stable PN nutrition requirement, determined by less than 5% reduction in PN nutrition calories for at least 1 month prior to screening, or at the discretion of the investigator.
6. Screening direct bilirubin that is in the normal range for age and is not determined to be clinically significant by the investigator.
7. Subject has an existing feeding tube, is receiving enteral nutrition via a pump at a rate\>10ml/hr but \<120ml/hr, and is able to tolerate at least 10 ml/kg/day enteral nutrition.
8. Stable enteral nutrition requirement with no change in formula composition or rate for at least 1 month prior to screening.
9. The parent or legal guardian of the patient is able to read, understand, and is willing to provide informed consent (and assent, if applicable).
10. The patient (if assent is applicable) or parent or legal guardian of the patient is able to understand the requirements of the study and is willing to bring the patient to all clinic visits and complete all study related procedures (as determined by the investigator).
A parent or legal guardian is willing to provide written authorization for the use and disclosure of protected health information.
Exclusion criteria:
1. Other causes of chronic liver disease other than SBS (i.e., hepatitis C, cystic fibrosis, biliary atresia, alpha 1 anti-trypsin deficiency, and Alagille syndrome).
2. The patient has had a bowel lengthening procedure, including but not limited to, a STEP procedure.
3. Any serum triglyceride concentration \>400 mg/dL at screening.
4. Pancreatic insufficiency as defined as the use of pancreatic enzymes within 30 days prior to screening.
5. Evidence of untreated intestinal obstruction or active stenosis, as determined by the investigator.
6. Unstable absorption due to cystic fibrosis or known DNA abnormalities (i.e., familial adenomatous polyposis, Fanconi syndrome) as determined by the investigator.
7. History of microvillus inclusion disease, as determined by medical history.
8. Severe known dysmotility syndrome (i.e., pseudo-obstruction, gastroschisis-related motility disorders), as determined by the investigator.
9. Initiation of teduglutide or other GLP-2 analogues within 6 months of screening
10. Use of growth hormone, or supplemental glutamine within 3 months prior to screening.
11. Use of cisapride within 30 days prior to screening.
12. Active clinically significant pancreatic or biliary disease, as determined by the investigator.
13. Patients are receiving formulas that are not compatible with the RELiZORB cartridge (example, insoluble fiber-containing formulas)
14. Determined by the investigator to be unsuitable for participation for any reason.
