Aim To evaluate the timeeffect and doseeffect of prasugrel hydrobromide acetic acid compound(PHAAC) inhibiting platelet aggregation.Methods For the timeeffect study, 190 SpragueDawley (SD) rats were devided into 19 groups (n =10) : the vehicle control group, the PHAAC groups (0.5, 1,2, 4, 6, 24, 48,72, 96 h) and the prasugrel hydrochloride groups (0.5, 1,2, 4, 6, 24, 48, 72, 96 h).Rats were singly intragastic administration of the vehicle, the PHAAC (5 mg · kg1) or the prasugrel hydrochloride (5 mg · kg1), respectively.Blood samples were taken at each time point for the determination of platelet aggregation rate (PAR).For the doseeffect study, 110 SD rats were devided into 11 groups (n =10) : the vehicle control group, the PHAAC groups (10, 5, 2.5, 1, 0.5 mg · kg1, dosage of prasugrel) and the prasugrel hydrochloride groups(10, 5, 2.5, 1,0.5 mg · kg1 , dosage of prasugrel).Blood samples were taken at 4 h after drug administration for the determination of PAR.Results Compared with the vehicle group, PHAAC has significant antiplatetet aggregative effects (P < 0.05) at the time of 0.5, 1, 2, 4, 6, 24, 48 h, and the effect at the time of 4 h was the strongest.There were no obvious differences between the effect of PHAAC (5 mg· kg1) and prasugrel hydrochloride (5 mg· kg1) at each time point.Compared with the vehicle group, intragastic administration of PHAAC at the doses of 10, 5, 2.5, 1,0.5 mg · kg1 could obviously inhibite the platelet aggregation, and showed a dosedependent manner.There were no significant differences between the effect of PHAAC and prasugrel hydrochloride at the same dose.Conclusion PHAAC can inhibit platelet aggregation in a dosedependent manner, and the effect at 4 h after drug administration is the strongest.The action strength and duration of PHAAC are similar with that of the prasugrel hydrochloride.