Objective: To observe the action of tonifying kidney prescription

invigorating spleen prescription and tonifying kidney and invigorating spleen prescription on the metabolism of calcium and phosphorus in tail suspension model rats. Method: Rats were assigned to five groups randomly:control(C)

tail suspended(S)

tonifying kidney (TK)

invigorating spleen(IS) and tonifying kidney and invigorating spleen (TKIS) groups. Rats in S

TK

IS and TKIS groups were suspended by head down tilt-30° for 21 days. Rats in TK

IS and TKIS groups were orally administrated with three decoctions and other groups with equivalent saline from the first day. Bone mineral density of left tibia was measured respectively using dual energy X ray absorptiometry in rats on day 22. Meanwhile calcium and phosphorus in serum and urine in rats of these five groups were measured by automatic biochemical analyzer. Calcium content in fecal and feed were detected by EDTA. Result: Compared with the C group

bone mineral density

serum calcium and phosphorus and apparent absorption rate of calcium are decreased

urine calcium and phosphorus and fecal calcium were increased obviously in S group. Compared with the S group

the bone mineral density

serum calcium and phosphorus

calcium intake and apparent absorption rate of calcium were raised but urine calcium and phosphorus and fecal calcium are reduced in TKIS group. Bone mineral density

serum calcium and phosphorus and apparent absorption rate of calcium were higher in TK and IS groups than the values in S group. Urine calcium and phosphorus and fecal calcium were lower in TK and IS groups than the values in S group. Calcium intake in IS group is increased above S group. Compared with the TKIS group

bone mineral density and serum calcium were decreased in TK and IS groups and apparent absorption rate of calcium was reduced in TK group. Conclusion: Three prescriptions including tonifying kidney prescription

invigorating spleen prescription and tonifying kidney and invigorating spleen prescription can improve the abnormal calcium and phosphorus metabolism caused by simulated weightlessness and the invigorating spleen prescription has a synergistic effect on tonifying kidney prescription in promoting calcium absorption and maintaining serum calcium concentration.