Objective: To study the effect of the extract of Selaginella tamariscina on the content of hydroxyproline in femur of ovariectomized rats. Method: Wistar rats were ovariectomized except for the normal group. One week after operation

the rats were treated with different medicines. Eleven weeks after treated the medicines

the rats were killed

the content of hydroxyproline in femur of ovariectomized rats was determined by RP- HPLC with pre-column derivatization by 2

4-dinitrochlorobenzene (DNCB). Result: Calibration curves showed good linearity within the concentration range of 0.125-2.00 g ·L-1 for hydroxyproline. The RSD of precision was less than 1%

the RSD of stability of the sample was less than 5% in 24 hours and recoveries of assay were 90%-110%. The water part group and n-butanol part group of S

tamariscina could increase the content of hydroxyproline in femur of ovariectomized rats. Conclusion: The extract of S. tamariscina can increase the content of hydroxyproline in femur of ovariectomized rats

suggesting that the water part group and n-butanol part group of S.tamariscina can intervene the osteoporosis in ovariectomized rats.