【Abstract】 The aim of this study was to investigate the initial time of platelet inhibiting effect of aspirin (ASA) and the effects of different doses on equilibrium of prostacyclin(PGI 2)-thromboxane B 2(TXB 2). The effects of 100 mg and 300 mg ASA on Platelet count, platelet aggregation rate, TXB 2 and PGI 2 were investigated using cross-compare way for 40 aspirin ingestion patients. The results showed that the platelet counts decreased to 33% after 30 minutes of single-dose ASA ingestion of 100 mg and to 25.6% after 60 minutes. TXB 2 and PGI 2 also decreased meanwhile. The platelet counts decreased to 39.5%, 35.5% and 26.6%, respectively with dose of 300 mg on day 1, 2 and 3. The platelet counts decreased to 38.1% and 39.5%, respectively, after 120 minutes with 100 and 300 mg ASA ingestion, without significent difference. In conclusion ASA begins to inhibit platelet function after 30 minutes of ingestion, and gives the strongest inhibition after 60 minutes. Continuous ASA ingestion accumulates the inhibitory effect. The single-dose ASA ingestion of 100 and 300 mg have nearly the same inhibitory effects.更多还原