Objective: To observe effects of Dan Wei Powder (胆胃散 Powder for treating the gall bladder and stomach) Tea Bag (DWSTB) on the aggregation rate of blood platelet in vivo and in vitro.Methods: Increase of the platelet aggregation rate in the rat in vivo was induced by carrageenin, and increase of the rabbit platelet aggregation rate in vitro was induced by adenosine diphosphate (ADP) and collagen, respectively. The effects of DWSTB on the platelet aggregation rate were investigated in vivo and in vitro, respectively.Results: The maximum in vivo platelet aggregation rate in the rat was significantly decreased after administration (P<0.05.P<0.01). And the effect of DWSTB on platelet aggregation was raised with increase of its dose.Conclusion: Dan Wei Powder Tea Bag can restrain the aggregation of platelet in vivo and in vitro.