The icteric male rabbits produced through ligation of common bile duct were employed for investigating not only the shifts of serum bilirubin glucuronide fraction but the change of formation of benzoyl glucuronide or hippuric acid after administration of benzoic acid and the following results were obtained. 1. The molar ratio of glucuronic acid to bilirubin in the serum decreased by ligating the
common bile duct, however, the ratio kept on nearly 1.0 even later than the 3rd day in the normal rabbits, while, the molar ratio in the rabbits with liver injury were more markedly depressed as compared to normal group and kept the value 0.55-0.45. The liver injury with chloroform and that with carbon tetrachloride showed no difference in the molar ratio. 2. No significant difference in 3 fractions of bilirubin fractionated by the method of Kosaka-Hara was found between normal rabbits and rabbits with liver injury after common bile duct ligation; almost all were equally occupied with ester form bilirubin, besides, no change could also be observed by the duration after common bile duct ligation. 3. The good correlation was found between molar ratio of glucuronic acid contained in ester form bilirubin to ester form bilirubin in serum and the grade of disturbance of the serum colloidal reaction. 4. In case that the grade of liver injury showed more than (+), molar ratio revealed less tkan 0.8, on tke other hand, no liver injury was found in the cases with 1.2 or more. 5. When benzoic acid was given to the normal rabbits with ligated common bile duct the excretion of benzoic acid or hippuric acid became minimum after 3 days and showed some recovery after 5 days, while, the excretion of benzoyl glucuronide increased after ligation of common bile duct, however, already revealed the tendency to decrease when the excretion of benzoic acid or hippuric acid reach minimum. It was considered from this results that a limitation seemed to exist in the substitutional effect of glucuronic acid conjugation. On the other hand, not only the excretion of benzoic acid but that of benzoyl glucuronide was diminished in the rabbits with liver injury as compared to normals, then it was concluded that the substitutional effect of glucuronic acid conjugation impaired in the case of liver injury.