Objective To evaluate the treatment effect of compound Chinese medicine on skeletal fluorosis in rats by Micro-CT.Methods Eighty-eight Wistar rats which had been weaned for two weeks were divided into four groups according to body weight [(91.1 ± 10.0)g] by the method of random number table:control group(16 mts),middle fluorine(MF)group(24 rats),high fluorine(HF) group(24 rats),and high fluoride and low calcium low protein (HF-LC-LP) group (24 rats).The amounts of fluorine of MF,HF and HF-LC-LP groups were 50,100 and 100 mg/kg,respectively.The contents of calcium and protein in HF-LC-LP group were half of MF and HF groups.Six months after treatment with fluoride,eight rats of each group were put to death with femoral artery bleeding.The rest 16 rats of each fluorosis group were divided into two groups,one was the control group and the other was fed with both fluorine and the compound Chinese medicine which simulated the actual situation of fluorosis area.Each rat of the treatment group was given the medicine 194 mg/100 g for six days every week.Daily urine samples were collected when the medicine had been used for 0,30 and 60 days.All the rats were put to death with femoral artery bleeding after the medicine had beengiven for 90 days,and limbs bones were dissected.Urine fluoride was tested by the method of fluoride ion selective electrode ; bone fluoride was tested by the method of high temperature ashing-fluoride ion selective electrode; bone mineral density(BMD),tissue mineral density(TMD),structure model index (SMI),trabecular thickness (Tb.Th),trabecular separation (Tb.Sp),anisotropy (a1/a3),trabecular connection density(Conn.D),the volume ratio of trabecular and bone tissue,the ratio of bone surface area and volume(BS/BV),and trabecular number(Tb.N) were detected by Micro-CT technology.Results The level of urinary fluoride of high fluoride and low calcium low protein treatment group [(11.01 ± 3.67)mg/L] was lower than that of its control group [(34.32 ± 9.50)mg/L,t =3.13,P ＜ 0.05] when rats were remedied with the compound Chinese medicine for 60 days.The level of bone fluoride of high fluoride treatment group[(275.38 ± 171.65)mg/kg] was lower than that of its control group[(701.67 ± 178.16)mg/kg,t =5.42,P ＜ 0.05] when rats were remedied withy the compound Chinese medicine for 90 days; bone fluoride of high fluoride and low calcium low protein treatment group[(313.26 ± 124.51)mg/kg] was lower than that of its control group[(794.66 ± 261.35)mg/kg,t =3.25,P ＜ 0.05].The differences of Tb.Th,Tb.Sp,a1/a3,Conn.D,BV/TV,BS/BV and Tb.N among groups were statistically significant(F =2.785,2.681,3.039,27.231,2.595,2.854,5.050,all P ＜ 0.05).Tb.Th[(0.04 ±0.01)mm] and Tb.Sp[(0.03 ± 0.01)mm] of middle fluorine treatment group were higher than those of their control groups[(0.02 ± 0.00),(0.02 ± 0.00)mm,all P＜ 0.05]; al/a3,Corm.D,BV/TV and Tb.N[(0.77 ±0.61),(510.91 ± 304.99)mm-3,(0.42 ± 0.06) and (13.58 ± 2.48)mm-1] were lower than those of their control groups[(1.11 ± 0.01),(2 403.69 ± 124.02)mm-3,(0.46 ± 0.03) and (18.12 ± 0.69)mm-1,all P ＜ 0.05].BV/TV(0.44 ± 0.04) of high fluoride treatment group were lower than those of their control groups(0.49 ± 0.00,P ＜ 0.05) ; Tb.Th[(0.04 ± 0.01) mm] was higher than that of its control group [(0.03 ± 0.00)mm,P ＜ 0.05].Conclusion The compound Chinese medicine may has therapeutic effect on rat skeletal fluorosis.