Sanhuang mixture (Xinmai capsule) is composed of Astragalus membranaceus, Coptis chinensis and Scutellaria baicalensis. It could inhibit platelet aggregation (PAG) induced by ADP in rats or by ADP and ADR in vivo. Patients with high PAG took Xinmai capsule for 4 weeks, the effective rate was 88.7%, which was same as the efficacy of aspirin 50 mg/day. In Syndrome Differentiation of TCM, the effective rate was the highest (92.3%) in the Syndrome of Qi Deficiency-Blood Stasis, and the lowest (72.7%) in the Syndrome of Stasis Phlegm and combined together.