Objective: To screen the active fraction of Yunnan Baiyao on the angiogenesis of chicken embryo chorioallantoic membrane(CAM). Method: Chicken chorioallantoic membrane angiogenesis model was used to compare the different extracted parts of Yunnan Baiyao. The different extracted parts of Yunnan Baiyao were implanted on top of CAM when chick embryos developed on day 7

at the same time

normal saline and suramin were given respectively as control group and positive group. The number of newly growth vessels were counted. Result: The vessel number of the ethyl acetate and alcohol (95%

80%

60%) extracted parts were largely less than that in the normal saline control group (P<0.01). Conclusion: The ethyl acetate and alcohol (95%

80%

60%) extracted parts had the activity of angiogenesis inhibition on CAM.