Aim To determine whether Xuezhikang, a HMG CoA reductase inhibito r made in China, affects CD11b expression and adhesiveness of monocytes to endot helial cells in vitro after the treatment of patients with hypercholesterolemia. Methods Fifteen patients with hypercholesterolemia were treated with Xuezhikang (1.2 g/d) for 4 weeks. Isolated human blood monoc ytes were subject to flow cytometric detection of CD11b and adhesion assays to l ive human endothelial cells were made before and after the treatments of Xuezhik ang. Results The average fluorescence intensity and the relative fluorescence intensity of CD11b expressed in monocytes and lymphocy tes from the peripheral venous blood were lowered after the treatment of Xuezhik ang. The expression rate of CD11b in lymphocytes was decreased from 27%±4% to 13%±3% (p<0.05,n=15). The adhesion rate of mo nocytes to endothelial cells was reduced from 5.5%±2.3% to 1.8%±0.8%(p<0.05,n=15). Pretreatment of CD11b mAb in vitro ca n inhibit the adhesion of monoctyes to endothelial cells. Conclus ions Xuezhikang, a kind of HMG CoA reductase inhibitor, can inhi bit the expression of CD11b in monoctyes and the adhesion of monocytes to endoth elial cells with the cholesterol loweing effects. The nonlipid mechanisms may involve in it.