The aim of the presented paper was to investigate the effects of chelidonine or Ukrain on the activity of serum aminotransferases AST and ALT in serum of tin-poisoned rats. The acute administration of tin chloride significantly increased AST and ALT activity in serum of rats in comparison in the control group. 10-day treatment with chelidonine (only in a dose of 100.0 mg/kg i.p.) significantly enhanced the activity of AST and did not affect the activity of ALT in the serum of tin-poisoned rats in comparison with the group receiving tin chloride only. However, 10-day treatment with Ukrain in doses of 7.0 and 14.0 mg/kg i.p. decreased the activity of ALT and increased the activity of AST (only in a dose of 14.0 mg/kg i.p.) in the serum of tin-poisoned rats.