In critically ill surgical patients, various therapeutic maneuvers are required to maintain a healthy gastrointestinal tract. Provision of adequate amounts of glutamine to the gastrointestinal mucosa and possibly to the gut-associated lymphatic tissue appears to be just one of these necessary maneuvers. The concept that the intestine is inactive after surgical stress merits reconsideration, as the intestinal tract plays a central role in interorgan glutamine metabolism and is a key regulator of nitrogen handling in this situation. Clinical studies to examine the benefits of glutamine-enriched nutrition in hospitalized patients are under way.