The aims of this study were: 1. the assessment of the nitrogen balance (NB) in both compensated and encephalopathic cirrhotics, 2. the evaluation of the efficacy of a new therapeutic approach: amino acid solutions enriched with branched chain (BCAA) but poor in aromatic (AAA) amino acids. Solutions containing only BCAA were also employed: 42 cirrhotics were divided into the following groups: 1st group (26 cases), cirrhosis without hepatic encephalopathy (HE); 2nd group (16 cases), cirrhosis with HE. Six patients (23%) in the 1st group showed a positive NB at the beginning; 20 (77%) were negative; 18 of them were fed an oral diet (0.8 g protein/kg/day; 35 cal/kg/day) as a result of which they were brought into a positive NB within 5 days (from - 7.38 +/- 0.95 to + 3.67 +/- 0.46 g N/24 h). In two cases the diet failed to give a positive NB, so it was replaced by a BCAA enriched solution infusion (NB raised from - 1.0 +/- 5.4 g N/24 h). Patients in the 2nd group were put on total parenteral nutrition (TPN); two cases receiving glucose alone achieved a positive NB only when BCAA enriched solutions were added (from - 4.0 to + 3.0 g N/24 h). Four patients treated for 3 days with BCAA alone did not achieve a positive NB; in these cases likewise, BCAA enriched solutions were added in order to achieve a positive NB (from - 0.8 to + 4.2 g N/24 h); all 14 cases treated from the beginning with glucose + BCAA enriched solutions became positive, on average, within 5 days (from - 4.82 +/- 0.89 to + 3.15 +/- 0.61 g N/24 h). In addition to the NB, other parameters (blood ammonia, BCAA/AAA ratio, blood urea, electroencephalograms) and clinical symptoms were beneficially influenced by these solutions.