Malnutrition in advanced cirrhosis may worsen liver function and increase susceptibility to infections. Immune-enhancing nutrition supplements (IENS) may be of value, but their safety in patients with decompensated cirrhosis and history of encephalopathy is unknown. We assessed the safety of Impact Recover (Novartis, St. Louis Park, MN), an orally palatable IENS, in 12 men with hepatic cirrhosis of Child-Turcotte-Pugh (CTP) class B or C, ages 40-60. On day 0, patients were evaluated serially for 6 hours after ingestion of 2 packets of Impact Recover. Despite a transient doubling of the blood ammonia, no cognitive abnormalities were noted on clinical assessment or psychometric testing. Subsequently, patients were instructed to ingest 3 packets per day of Impact Recover for 56 days, after which supplements were stopped. Patients were evaluated in a fasting state on days 0 (baseline), 56 (end of treatment), and 112 (follow-up). One patient was transplanted on day 21, and another died after an urgent cholecystectomy on day 30. The remaining 10 patients completed the study. Mean value of CTP score was 9 (range, 7-11) and mean value of model for end-stage liver disease (MELD) score was 14 (7-21), and there was no change after 8 weeks of IENS. Only 1 experienced transient worsening of encephalopathy after omitting lactulose. Performances on psychometric tests did not change. Transferrin levels increased rapidly with IENS, then returned toward baseline after IENS was stopped. Fasting insulin and peptide YY (PYY) levels also increased, but fasting glucose and hemoglobin A1C did not change. Trends in other nutrition and immune parameters did not reach significance. We conclude that acute and chronic administration of Impact Recover was well tolerated in cirrhotic patients with controlled encephalopathy. Further studies are justified to assess potential efficacy of long-term IENS in preventing infection and slowing progression in advanced cirrhosis.