In is known that cancer research has been concentrated to make a correlation between cancer and its bearing hosts. An attempt was made to study anticancer effect and enzyme metabolism under the administration of anticancer agents and their supporting substances in order to destruct cancer cells and increase biological resistance of its bearing mice. The results obtained are as follows: 1) Marked prolongation in survival period and inhibition of ascites were obtained in cancer bearing mice under mitomycin administration, but the administration of its large dosage in contrast, inhibited a prolongation of survival period and also made a loss of body weight. The combined administration of anticancer agents and their supporting substances manifested the most remarkable prolongation in survival period. Amongst three anticancer supporting substances, orotic acid made the greatest prolongation of survival period as well as marked inhibition of ascites. Glucuronic acid made the same results in less degree. 2) Mitomycin had a marked effect to inhibit the depression of catalase activity in liver and kidney of cancer bearing group, although mitomycin itself had a tendency to decrease catalase activity in liver and kidney of normal group. 3) Anticancer supporting substances, orotic acid and glucuronic acid markedly increased catalase of liver in normal group and inhibited the tendency of its decrement in cancer bearing group. 4) Anticancer agents showed the same tendency to saccinic dehydrogenase activity as to catalase. 5) S-GOT and S-GPT slightly increased in cancer bearing group. They were intensively improved under the combined administration of anticancer agents and their supporting substances.