This is an expanded access study to assess the safety profile and changes in serum direct bilirubin levels in infants with PN associated cholestasis. Eligible patients will receive therapy with Omegaven on an expanded access basis by method of continuous infusion. Omegaven will be infused intravenously through either a central or peripheral catheter in conjunction with parenteral nutrition. The same standards of care provided to all patients receiving parenteral nutrition solution will be followed.

This expanded access protocol provides a mechanism for critically ill infants with parenteral nutrition-associated liver disease (PNALD) to receive Omegaven for compassionate use situations for which there are no satisfactory alternative treatments.

Inclusion Criteria:

• Greater than 4 weeks (28 days) old and less then 5 years of age
• Diagnosis of PNALD as defined by serum direct bilirubin greater than 2 mg/dL on 2 consecutive occasions
• Expected to require intravenous nutrition for at least an additional 28 days
• Have been PN-dependent for at least four weeks prior to planned Omegaven initiation
• PN-dependent and unable to meet nutritional requirements by enteral means
• Have failed standard therapies to prevent progression of PNALD
• Hospitalized at time of Omegaven initiation

Exclusion Criteria:

• Have a congenitally lethal condition (e.g. Trisomy 13).
• Have evidence of a viral hepatitis or primary liver disease as the primary etiology of their cholestasis.
• Have other health problems such that survival is extremely unlikely even if the infant's cholestasis improves.
• Have been in another clinical trial within 30 days prior to enrollment or received an investigational drug within 30 days prior to enrollment or scheduled to receive an investigational drug other than Omegaven during the study period.
• Severe and/or unstable concomitant systemic disease such as complex congenital cardiac disease, renal failure, autoimmune disease, sepsis, inborn error of metabolism, genetic liver disease
• Bleeding disorder
• Biochemical disturbance with potential of worsening with proposed treatment, e.g. persistent hyperglycemia, hypertriglyceridemia, hypercalcemia.