A study was conducted to investigate the cumulative survival rates among groups of patients with liver cirrhosis who were stratified by plasma branched-chain amino acid (BCAA)/aromatic amino acid (AAA) molar ratio (BCAA/AAA), and to evaluate the effect of long-term oral supplementation with BCAA on the prognosis of cirrhotics with noticeably lower BCAA/AAA molar ratio. When 104 patients with liver cirrhosis were divided into three groups on the basis of BCAA/AAA molar ratio, i.e., BCAA/AAA greater than or equal to 1.8 (Group 1), 1.8 greater than or equal to BCAA/AAA greater than or equal to 1.0 (Group 2), and 1.0 greater than BCAA/AAA (Group 3), Group 1 showed the highest cumulative survival rate, followed, respectively, by Groups 2 and 3 (P less than 0.05). In 20 cases of non-alcoholic liver cirrhosis having BCAA/AAA less than 1.8, oral supplementation with branched-chain amino acid granules (BCAA-G) for 6 months or more (median 27 months, range 7-62 months) brought about significant increase of plasma BCAA concentration, BCAA/AAA molar ratio, and serum albumin concentration. Furthermore, the 20 cases with BCAA-G supplementation showed significantly higher cumulative survival rate during 2-4 years as compared to the control cases matched for age, sex, and etiology (involvement of hepatitis B virus). These findings indicate that long-term oral supplementation with BCAA to cirrhotic patients provides beneficial effect on the prognosis by improving protein malnutritional status and consequently delaying fatal complications such as hepatic failure and gastrointestinal bleeding.