The pharmacokinetics of propranolol administered orally (10 me/kg) was investgated in the rabbits of carbon tetrachloride induced hepatic failure. The plasma concentration and relative bioavailability of propranolol were increased significantly in hepatic failure rabbits, compared with those of normal rabbits. There were significant relationship between GOT, GPT value and bioavailability parameters of propranolol. In short, dosage regimen of propranolol is considered to be adjusted in dose size and dosing interval using GOT or GPT an index.