PURPOSE OF REVIEW: To summarize recent research addressing the role of enteral fish oil supplementation in critical illness. RECENT FINDINGS: A number of new multicenter trials examining both the use of fish oil given as a supplement to enteral nutrition support and given as a separate bolus, independent of nutrition delivery, have recently been reported. SUMMARY: Mechanistic data suggest that administration of fish oil may help attenuate the systemic inflammatory response and allow for appropriate resolution of inflammation in critically ill patients. Recent data indicate that enteral fish oil given as a continuous infusion as part of complete nutrition improves outcome in critically ill patients, especially those with acute lung injury/acute respiratory distress syndrome. In contrast, the bolus administration of fish oil cannot be recommended as clinically beneficial in acute lung injury/acute respiratory distress syndrome patients. Recent trials indicate that pharmacologically administered nutrients should be studied in the same manner as other new drugs, with appropriate attention to early dosing trials, proper pre-enrollment patient selection, and understanding of the role of concomitant protein/calorie nutrition. More research continues to be needed to optimize the proper patient, dose, and timing of administration for enteral fish oil therapy in the ICU.