Development of amino acid solutions for i.v. use proceeds worldwide, the main stimulus being the expanding physiological and pathophysiological findings of specific effects of some amino acids and their metabolism and the need to improve intensive metabolic care. New Czech preparations in this respect are the series of NEONUTRINS 5%, 10% and 15% (Infusia Ltd. Horátev). They are modern preparations which meet the pretentious criteria of contemporary amino acid solutions (balanced ratio of all essential, semiessential and assisting amino acids, a high content of essential and branched-chain amino acids, amino acids with specific pharmacodynamic effects). In a multicentre open clinical study the authors assessed the tolerance, safety and efficacy of NEONUTRIN 15% in 82 patients requiring total parenteral nutrition on account of catabolic states of different etiology. The preparation was administered repeatedly in an all-in-one mixture (together with glucose and lipid emulsions) by means of a central venous catheter. A total of 801 doses was administered. The trial provided evidence of very good tolerance and safety of the preparation with a practically zero incidence of undesirable effects. The follow-up of basic indicators of nitrogen metabolism confirmed also the efficacy of NEONUTRIN 15% in comprehensive treatment of patients (stabilization of nitrogen balance in the acute stage of a disease, normalization of the plasmatic aminogram).