The effect of shark cartilage active extract (SCAE) on the lung metastasis and the immune function were studied in C57 mice with oral administration. The formation of pulmonary metastasis (B16 melanoma)was significantly inhibited, with an inhibitory rate of 33. 1%. The proliferation rate of spleen cells to ConA was obviously increased,the increased rate being as high as that of the normal. The cytotoxicity of LAK cells is also increased,but lower than that of the mormal.