Objective To study the mechanism of Bushen Granule (G ranule for rein forcing the kidney) for the treatment of chronic aplastic anemia (CAA). Methods The CAA patients were divided into the herbal group (60 cases) treated mainly by Bu shen Granule with syndrome differentiation and the Cyclosporin A group (16 cases ) tr eated mainly by Cyclosporin A for 6 months. The healthy control group consisting of 20 healthy subjects was set up. The expressions of CD3 +, CD3+CD28+, and CD3+CD95+ of the healthy control groups were compared with the herbal group and the Cyclosporin A group. Results The expressions of CD3 +, CD3+CD28+, and CD3+CD9 5+ of the CAA groups were higher than those of the healthy control group (P