To determine whether bleomycin A 5 can inhibit angiogenesis and cancer metastasis. Methods: 1.The pellet contained 0.5μg bleomycin A 5 was placed onto the 7th day chick embryo chorioallantoic membrane, and antiangiogenesis activity was to be observed 48d later, 2.At the 6th day after Lewis lung carcinoma was inoculated s.c. into the right flank of C 57 BL/6 mice, bleomycin A 5 was topically injected around and beneath the inoculum, 0.6mg per mouse, once every 5 days, and 3 times totally. All mice were sacrificed on the 25th day after tumor implantation. Tumor angiogenesis and lung metastatic foci were examined. Results: 1.A vessel decreased or avascular zone appeared on the chick CAM around the pellet which contained bleomycin A 5. 2. After administration of bleomycin A 5, subcutaneously inoculated tumors were smaller than those of controls, and looked pale with sparse capillaries. Necrosis could be seen commonly. The percent inhibition of lung metastatic foci was 80%. Conclusion: Bleomycin A 5 can inhibit angiogenesis both on the chick CAM assay and in s.c. Lewis lung carcinoma model. Furthermore, it has a markedly antimetastatic effect.