Prolonged stay of patients is the major challenge for modern intensive care because of its effects on morbidity and resource utilization. Severe trauma or infection are associated with the catabolic response, characterized by increased protein turnover and negative nitrogen balance. Severe catabolism leads to end-organ dysfunction and muscular weakness prolonging the need for mechanical ventilation. Catabolism cannot be prevented with standard parenteral or enteral nutritional formulas. In order to prevent the complications of catabolism in intensive care patients, recombinant growth hormone (rhGH) has been applied during two decades as an experimental therapy for patients requiring parenteral nutrition and for those with respiratory failure. Administration of rhGH has resulted in positive nitrogen balance, and studies in mechanically ventilated patients suggest that it may shorten the need for ventilatory support. In contrast to the results of these relatively small studies, a recent multinational randomized controlled trial revealed that the administration of rhGH (with doses 10-20 times higher than those used for replacement therapy) increases the mortality of critically ill patients. This excessive mortality in patients treated with rhGH was related to infections and development of multiple organ failure. Administration of high doses of rhGH to critically ill patients cannot thus be recommended.