AIM:To observe the preventive and therapeutic effects of sarsasapogenin(SAR) on retinoic acid induced osteoporosis in mice.METHOD: The mice osteoporosis was induced by given retinoic acid intragastrically for two weeks.At the endpoint,the thymus,spleen and uterus were weighed separately;the femoral dry weight,bone-calcium,phosphor,magnesium and hydroxyproline contents of femoral were measured;the histomorphological features of bone were observed and the biochemical indexes in serum(Ca,P,ALP,TRAP,E_(2),BGP) were determined after the mice were given SAR at the dose of 10,30,90 mg·kg~(-1) respectively,and were compared with the model group,the normal control and the positive control.RESULTS:The osteoporosis of high turnover type was formed with feeding retinoic acid to experimental mice.Compared with the model group,the lessening of femoral dry weight,the short femoral transverse diameter,the decrease of bone mineral and bone-hydroxyproline of SAR groups were improved.At the same time,the E_(2) and BGP level in SAR groups,especially the middle and high dosage group was obviously higher than that of the model group,while the s-ALP and s-TRAP levels were lower than the model group.CONCLUSION:SAR can prevent the loss of bone in the experimental mice.The mechanism may be that it improves the level of estrogenic hormone and inhibits the high bone turnover.