Abstract: AIM: To study the inhibitory effect of Fascaplysin on the growth of transplanted S180 tumor in ICR mice. METHODS: The LD₅₀ was counted by LD₅₀ 1.01 software for acute toxicity test. Mouse models bearing S-180 tumor were established by subcutaneous injection in ICR mice, randomly divided into 4 groups: control group (injection of saline), positive control group (CTX, 30 mg·kg^-1·d^-1) , high dose group (Fascaplysin, 20 mg·kg^-1·d^-1) and low dose group (Fascaplysin, 5 mg·kg^-1·d^-1). The growth and histopathological changes of the tumors were observed 10 d after the corresponding treatment of all groups. RESULTS: The growth inhibition rates of positive control group, high dose group and low dose group were (53±9)%, (52±10)% and(30±12)%, respectively.Compared with the control group, there were no significant histopathological changes in liver and kidney of ICR mice during the administration of Fascaplysin, but there were significant changes in transplanted S180 tumor. CONCLUSION: A certain dose of Fascaplysin can significantly inhibit the growth of transplanted S180 tumor in ICR mice. It is a potential antitumor lead compound.

Key words: Fascaplysin, ICR mice, S180, Antitumor effect