To study the effects of centipede extracts on H22 tumor-bearing mouse, sarcoma S180 mouse and normal mouse. Normal and tumor-bearing mouse were orally administrated by centipede extracts. Rate of restraining tumor, index of thymus and spleen were calculated after 12 days treatment. Acute toxicity testing tried to figure out In LD50 of centipede extracts. The restraining tumor rates of centipede ethanol extracts at low and medium doses were 22.2% and 17. 88%. There was no tumor restraining effect by the high dose treatment. The tumor growth of the H22 model mouse was not restrained by the centipede water extracts. There were no significant differences among the treatments in their spleen weight and spleen index. In LD50 test, the administrating dosages of centipede extracts given to the mouse were 48 times those given to patients on clinic. The result showed no mouse dead in centipede group. Centipede water extracts had no anti-tumor effect on tumor-bearing mouse. There is certain toxicity in ethanol extracts of centipede, suggesting that centipede alone for treatment of cancer needs further study.