BACKGROUND:Salvia miltiorrhiza bone-setting capsule is a traditional Chinese medicine for the treatment of fractures due to activating blood circulation to dissipate blood stasis, reducing sweling and pain. OBJECTIVE: To observe the effects of Salvia miltiorrhiza bone-setting capsule on the fracture healing in a rat model of closed femoral fractures. METHODS: Rats were randomly divided into salvia miltiorrhiza bone-setting capsule group, physiological saline group and normal group. In the salvia miltiorrhiza bone-setting capsule group and physiological saline group, rat models of closed femoral fractures were prepared, and then given physiological saline and salvia miltiorrhiza bone-setting capsule 2 pils by intragastric administration. In the normal group, rats were housed normaly. At 7, 14 and 28 days after fractures, hematoxylin-eosin staining conditions, serum osteocalcin, the expression of colagen type I, and the expression of protein and mRNA calus transforming growth factor-beta 1 were observed in the salvia miltiorrhiza bone-setting capsule group and physiological saline group. RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining demonstrated that at 7 days after fractures, no significant difference was found in pathological changes of femoral fracture in salvia miltiorrhiza bone-setting capsule group and physiological saline group. At 14 and 28 days after fractures, pathological repair was more obvious in the salvia miltiorrhiza bone-setting capsule group than in the physiological saline group. (2) At 3 and 7 days after fractures, serum osteocalcin and the expression of type I colagen were significantly increased in the salvia miltiorrhiza bone-setting capsule group and physiological saline group (P < 0.05), and the expression trend was consistent in both groups. The expression was always higher in the salvia miltiorrhiza bone-setting capsule group than in the physiological saline group, and significant differences were found at 14 and 28 days after fractures (P < 0.01). (3) Transforming growth factor beta 1 expression reached a peak at 3 days after fractures, gradualy reduced, increased at 14 days (the second peak), and diminished at 28 days in the salvia miltiorrhiza bone-setting capsule group and physiological saline group. The expression trend of transforming growth factor beta 1 was consistent in the salvia miltiorrhiza bone-setting capsule group and physiological saline group. At 7, 14 and 28 days, the transforming growth factor beta 1 expression was higher in the salvia miltiorrhiza bone-setting capsule group than in the physiological saline group. (4) Results showed that salvia miltiorrhiza bone-setting capsule could promote fracture healing, and its mechanism was probably associated with serum osteocalcin, the expression of colagen type I and transforming growth factor-β1.