Dietary supplements of n-3 fatty acids have long been used to influence chronic inflammatory disorders. Recent studies with an immune-enhancing diet partly based on n-3 fatty acids report beneficial effects in patients with acute hyper-inflammatory diseases, such as the sepsis syndrome or adult respiratory distress syndrome (ARDS). The possible suppression of exaggerated leucocyte activity, the improvement of microcirculatory events, as well as the opportunity to administer intravenous lipids enriched in n-3 fatty acids signal the possibility of a combination of parenteral caloric support and pharmacological intervention. Using parenteral administration of fish oil-based lipids, a new rapid and highly effective anti-inflammatory agent may allow the option to alter the immune status in hyper-inflammatory diseases such as sepsis and ARDS.