The hypermetabolism that develops in patients with severe polytraumatism has led to the need for an aggressive metabolic-nutritional support from the start. Parenteral Nutrition is the preferred technique in many instances, due to the doubts on the effectiveness of enteral nutrition in the control of the metabolic response and to problems of gastrointestinal tolerance derived from its administration. However, the role of enteral nutrition as an important factor which limits the development of bacterial translocation and the chain of events leading to multiorganic failure appears to be more and more well-established and is an important argument for justifying the early administration of enteral nutrition in these patients. In accordance with the accumulated experience of several authors over the past few years, enteral nutrition may be administered early in polytraumatized patients. This is not only accompanied by the evidence of acceptable gastrointestinal tolerance to the diet, but also by additional advantages compared to parenteral nutrition, such as the maintenance of trophism and immunocompetence of the digestive mucosa, the reduction of septic complications and also greater nutritional effectiveness which can be evaluated by the behaviour of the seric proteins used as nutritional evolution markers. The interest of the different diet formulae which exist at present, for example diets enriched with branched-chain amino acids, diets with added fibre, peptidic diets, specific pulmonary diets or "euglycaemic diets" is evaluated in this review. All these diets may mean an increase in the effectiveness and/or tolerance of enteral nutrition in polytraumatized patients, and also contribute to the handling of specific problems such as "stress" hyperglycaemia or the withdrawal of mechanical ventilation support. The use of specific nutrients for the digestive mucosa, such as glutamine or short chain fatty acids seems to be an important factor in the reduction of bacterial translocation. The new concept of immunonutrition is opening up new expectations with regard to the possibility of reducing septic complications, which often lead to problems in the evolution of patients, by means of nutritional manipulation. Current knowledge has permitted the early administration of enteral nutrition in polytraumatized patients, although on occasions the nutritional requirements will have to be administered by the complementary use of enteral and parenteral nutrition.