The intravenous administration of fructose in healthy subjects may induce an increase of blood uric acid and the urinary excretion of urate and xanthine as a result of hepatic adenosine triphosphate (ATP) breakdown. These changes are partially reversed by ATP resynthesis. We studied the effect of fructose load (0.5 g/kg body weight) on the products of ATP metabolism, and the interference of fructose on the galactose test in 10 patients with well compensated cirrhosis compared with 10 healthy controls. The fructose and the fructose/galactose loads induced a significantly greater increase of plasma uric acid in cirrhotics than in controls, with a 60 minute peak in the cirrhotics. Urinary excretion of urate and xanthines was significantly increased (p less than 0.001) only in the cirrhotics after the fructose/galactose load. As expected, the galactose elimination capacity (GEC) calculated with the galactose test, was lower in these patients than in controls. Fructose infusion before galactose did not significantly modify the GEC in either of the two groups compared. The higher uric acid increase induced by fructose in the blood of cirrhotic patients seems to be a good marker of the energy crisis of the diseased liver whereby it is unable to efficiently resynthesize ATP from its breakdown products.