Abstract: In a previous paper, the SGPT-lowering action of BDD in mice intoxicated with CCl₄ or thioacetamide as well as in prednisolone treated mice was reported. The present data indicate that BDD also has significant protective action against liver lesions induced by CCl₄ in mice. In addition, BDD was found to decrease the liver GPT (glutamate pyruvate transaminase) activity of normal, CCl₄-intoxicated and prednisolone-treated mice. However, no effect of BDD on GOT (glutamic oxaloacetic transaminase) and aldolase activities were observed. Although liver GPT was significantly decreased by BDD, the heart GPT still remained in normal level. Incubation of the serum of mice given BDD with the liver homogenate of CCl₄-intoxicated mice at 37℃ for 2 hours in vitro, no decrease of GPT activity of the liver homogenate was obtained. Moreover, no speed up of spontaneous decrease of serum GPT level in mice injected with 5ml/kg of high GPT serum (from CCl₄-intoxicated mice) by BDD was found. Therefore, it seems that the SGPT-lowering action of BDD is not due to direct inhibition of serum and liver GPT activities or to the increase of spontaneous disappearence of GPT from mouse blood circulation. The exact mechanism of the protective action of BDD against liver injury in animal remains to be elucidated.