In these experiments, two kinds of extracts, Mytilus cornin-nondialyzable fraction and Mytilus Li-ethanol fraction, were used to study the inhibitory effects on Ehrlich ascites carcinoma. And also investigated the comlexing action of extracts with ZnCl(2), MnCl(2), CuCl(2) and adrenaline. In studying carcinostatic action the author used ddN strain mice. These were inoculated routinely with 1×10(7) Ehrlich ascites tumour cells in a volume of 0.2ml of ascites fluid. Then 48 hours after inoculation, treatment with the extracts was begun. Each day for five days, each one of the mice was given intraperitoneally injection with a solution containing 5-20mg of the material per 0.5ml of saline. Obtained results are summarrized as follows. 1) Mytilus cornin and Mytilus cornin-nondialyzable fraction had no effect on ascites bearing mice. 2) 5-20mg of Mydilus cornin-nondialyzable fraction in 10(-5)～10(-6)M of ZnCl(2)-saline injected intraperitoneally into ascites bearing mice for five days produced a marked reduction in mean body weight and an increse in survival time. 3) In the cace of MnCl(2) and CuCl(2) a similar effect was demonstrated in the reduction of body weight, but not in sarvival time. 4) Mitilus Li-ethanol fraction in saline led to inhibition of Ehrlich carcinoma, and also an increase in survival time, when it was given intraperitoneally at dose level of 10mg per mouse on the seconed day after tumour transplantation and continued for each of five days. 5) Mulilus Li-ethanol fraction in heavy metal ions and adrenaline had no effect on ascites bearing mice.