The aim of this study was to asses hepatoxicity of riamilovir with repeated administration on the animal model. Materials and methods. Twenty non-linear guinea pigs were randomized into 4 groups: control and three experimental, receiving 64 days of daily riamilovir orally in doses of 48, 96, 144 mg/kg. Biochemical profile: ALT, AST, GGT, total protein, total and direct bilirubins, albumin, cholesterol, triglycerides: on 0, 33 and 65 days from the start of the experiment. Results. A significant decrease of serum albumin and cholesterol levels was found only in group 2 and there were no statistically significant changes of other indicators. Conclusion. The data obtained indicate afunctional liver synthetic function changes without signs of hepatobiliary and hepatocellular damage.