Objective To investigate the changes in endothelial progenitor cells (EPCs) number in peripheral blood of patients with acute cerebral infarction and after Naoxintong treatment.Methods Sixty patients were selected as subject and randomly divided into aspirin group and aspirin (30 patients) + Naoxintong group (30 patients).Meanwhile 30 patients without cerebral infarction were served as control group The number of peripheral blood EPCs were detected by flow cytometry at different time point.NIH-NINDS stroke score was used to elevate the neurological function.Results Compared with the control group,number of peripheral blood EPCs significantly decreased in the early stage of acute cerebral infarction (P ＜ 0.05),and then gradually increased until 7th day,which was back to the normal level.There was a positive correlation between improvement of NIHSS and number of peripheral blood EPCs in acute cerebral infarction.Compared with aspirin group,the number of peripheral blood EPCs in Naoxintong group increased sigrificanfly [41.40 ±0.18/million cells vs 41.40 ±0.18/million cells] at 14th day in patients treated with aspirin and Naoxintong.Conclusion The number of peripheral blood EPCs showed a U shape dynamic change in acute cerebral infarctior.Increase the number of peripheral blood EPCs might improve prognosis in patients with acute cerebral infarction.On the basis of routine treatment of aspirin,Naoxintong plus aspirin treatment might improve the number of peripheral blood EPCs in acute cerebral infarction.