The benefit of enteral nutrition in critically ill patients has been demonstrated by
several studies, especially when it is started early, in the first 24---48 h of stay in the Intensive Care Unit, and this practice is currently advised by the main clinical guidelines. The start of enteral nutrition is controversial in patients with hemodynamic failure, since it may trigger intestinal ischemia. However, there are data from experimental studies in animals, as well as from observational studies in humans that allow for hypotheses regarding its benficial effect and safety. Interventional clinical trials are needed to cofirm these findings