Objective To explore the therapeutic mechanism of blood- activating and blood- stasis- removing (BABAR) therapy for polycythemia vera (PV).Methods Ten first- visit or un- relieved outpatients and inpatients were treated with BABAR therapy for 12 weeks. Healthy volunteers served as the normal control. Before treatment and 1, 4, 8 and 12 weeks after treatment, the apoptotic rates of bone marrow mononuclear cells (BMMC) was analyzed with the TUNEL method. The expression of bcl- 2 and p53 was observed by the method of immunohistochemistry and their mRNA expression by the method of hybridization in site.Results One, four and eight weeks after treatment, the apoptotic rates of BMMC was increased as compared with those before treatment (P 0.05).The gene expression level of Bcl- 2 and p53 and their RNA expression level in the patients before treatment were higher than those in the normal control(P