The etiology of parenteral nutrition associated liver disease (PNALD) is currently considered multifactorial. Available treatment options for this disease process are limited and have achieved moderate success at best. Unlike conventional intravenous fat emulsions, Omegaven™ is comprised solely of fish oils containing primarily omega-3 fatty acids. The investigators hypothesize that administering Omegaven™ to patients with PNALD in place of conventional fat emulsion may reverse cholestasis allowing patients to be maintained on adequate PN until they are able to ingest adequate nutrition enterally.