Objective To explore the possible action mechanism of Erxian Decoction（ 二仙汤） in the treatment of osteoporosis. Methods Osteoblasts were inoculated into 96-well plates at 5 × 103 holes and divided into normal group

model group

estradiol valerate group and Erxian Decoction high

medium and low dose groups

with 6 holes in each group. All groups except the normal group

were cultured in complete medium containing 600 μmol/L hydrogen peroxide（ H2 O2） for 3 h to induce osteoblast formation model. The normal group was cultured with blank control serum. The estradiol valerate group was given serum containing 8% valerate estradiol

and the Erxian Decoction high

medium and low dose groups were given 8%

4%

2% Erxian Decoction respectively. The drug-containing serum was cultured for 48 h. The osteoblast proliferation

alkaline phosphatase（ ALP） activity

calcium nodule formation

and the expression of bone morphogenetic protein 2（ BMP-2） and osteoprotegerin（ OPG） protein were detected. In addition

the intervention of Nifdipine（ 10 μmol/L） was used to observe the effects of Nifdipine on cell proliferation

ALP activity

BMP-2 and OPG protein expression after H2 O2 induced osteoblasts and its effects under the intervention of Nifdipine. Results Compared with the normal group

cell proliferation

ALP activity

calcium nodules and BMP-2 expression were decreased in the model group（ P < 0. 05 or P < 0. 01）. Groups with different doses of Erxian Decoction could promote osteoblast proliferation

increase ALP activity and calcium nodule formation

and promote BMP-2 and OPG protein expression（ P < 0. 05 or P < 0. 01）. Nifdipine could increase BMP-2 and OPG protein expression of osteoblasts induced by H2 O2（ P < 0. 05 or P < 0. 01）. The combination of serum containing Erxian Decoction and Nifdipine could significantly increase the proliferation of osteoblasts induced by H2 O2 and decrease the expression of BMP-2 and OPG protein as compared with simple use of Nifdipine（ P < 0. 01）. Conclusion The serum containing Erxian Decoction can significantly improve the effect of oxidative stimulation on the formation of osteoblasts

the mechanism may be related to the regulation of calcium channels.