Objective To observe the effect of tortoiseshell on the bone mineral density（BMD） and bone strength of lumbar vertebrae and tibia in glucocorticoid-induced osteoporosis rats. Methods Forty-eight SD rats were randomized into blank group

model group

western medicine group and tortoiseshell group

12 rats in each group. Dexamethasone was injected subcutaneously to make the osteoporosis model in the model group

western medicine group

and tortoiseshell group. After modeling

the western medicine group was treated with alendronate sodium63 mg/kg orally once every 7 days; the tortoiseshell group was treated with tortoiseshell 30 mg/（kg ·d） by gavage once a day; the blank group and the model group were treated with 0. 9% chlorine sodium solution 2 ml by gavage once a day. All groups were administered for 3 months. The BMD and bone strength of lumbar vertebrae and tibias were measured before treatment

2 months and 3 months after administration. The BMD and bone strength improvement rate of western medicine group and tortoiseshell group were calculated 3 months after administration. Results In the tortoiseshell group

the BMD of lumbar vertebrae and tibia increased 2 and 3 months after administration

so did the strength of tibia; the intensity of lumbar vertebrae also increased 3 months after administration（P < 0. 05 or P < 0. 01）. Three months after administration

the BMD and bone strength of lumber vertebrae and tibia in the western medicine group and the tortoiseshell group were all higher than those in the model group（P < 0. 05 or P < 0. 01）.The BMD of lumbar vertebrae was lower in the tortoiseshell group than in the western medicine group（P < 0. 05）

but there was no significant difference in the lumbar vertebrae bone strength and tibia BMD and bone strength（P >0. 05）. After 3 months of administration

in the tortoiseshell group

the BMD improvement rate of lumber vertebrae was 8. 08%

of tibia 8. 30%

the strength improvement rate of the lumber vertebrae was 44. 67%

of tibia 30. 58%.Conclusion The tortoiseshell could improve the BMD and bone strength of lumbar vertebrae and tibia in glucocorticoid-induced osteoporosis rats

and has a better effect on the improvement of bone strength of lumbar vertebrae than of tibia

and has an equal effect on the improvement of BMD.