Objective To investigate the effect of aspirin on platelet biochemical index in patients with cardio-cerebrovascular diseases and the influence of Naoxintong（Brain-heart unobstruction）Capsule.Methods The blood samples of 215 patients taking aspirin 100 mg per day for 7 days were collected for determination of platelet aggregation（PAG）

P-selection level and TXB2 level by using arachidonic acid（AA）and adenosine diphosphate（ADP）.Then they were divided randomly into aspirin group 1（n=72）

still taking aspirin 100mg per day

aspirin group 2（n=70）

taking aspirin 300mg per day

and Naoxintong group（n=73）

taking aspirin 100mg per day and Naoxintong Capsule.One month later

their PAG

P-selection and TXB2 levels were re-examined.Results The plasma P-selection and TXB2 were in a positive correlation with AA-and ADP-induced PAG（P<0.01）.The plasma P-selection was in a positive correlation with TXB2（P<0.01）.After treatment

the AA-and ADP-induced PAG

P-selection and TXB2 among three groups were significantly lowered（P<0.01）.In the Naoxintong group

the AA-and ADP-induced PAG

P-selection and TXB2 were lower than those of aspirin groups（P<0.05）

and the ADP-induced PAG was obviously lower than that of aspirin group 1（P<0.05）.There was no significant difference in the side-effect incidence among three groups.Conclusion The combination of Naoxintong with aspirin can reinforce the effect of antiplatelet without increased side-effect.