Metabolisms of serum protein and electrolytes in cancer bearing mice were studied to correlate with the effect of anticancer agents and their supporting substances administration. The results obtained are as follows: 1) Serum albumin was decreased in course of cancer progress, which was in negative correlation with ascites increment. 2) Serum Ca tended to decrease, K to increase and Na to fluctuate erratically. 3) The combined administration of anticancer agents and their supportiog substances improved more the liver function to accelerate the assimilation of serum protein and the anticancer resistance, and also improved more serum Ca metabolism than single administration of the anticancer agents in cancer bearing mice.