To study and evaluate the effect of Sangu Decoction (SGD, a parts per thousand e(a)ae +/- currency sign) on the bone destruction due to mammary cancer metastasis. Metastasis rat mammary tumor-1 cells were transplanted into the left hind limb tibia of SD rats to establish the bone metastasis of the mammary cancer model. The modeled rats were treated with SGD for observing its effect on rats' pain behavior, including 50% paw withdrawal threshold (50% PWT) after von Frey fiber stimulation, burden difference of bilateral feet, and thermal withdrawal latency (TWL), with zoledronic acid as the positive control. Moreover, the damage in the tibia sample of rats was scored by an iconographic method, and the bone mineral density (BMD) as well as the bone mineral content (BMC) were estimated. The model established showed characteristics of mixed metastasis, revealing the manifestations of tumor development, bone destruction, cancerous pain, etc. In the SGD-treated group, 50% PWT was prolonged (8.13 +/- 4.76 vs. 2.30 +/- 2.19), and TWL was longer (3.48 +/- 0.62 s vs. 2.89 +/- 0.26 s) than those in the control group, respectively (P < 0.05 or P < 0.01). Iconographic scoring also showed improvement of BMD (0.134 +/- 0.009 vs. 0.120 +/- 0.007, P < 0.01) and an elevating trend of BMC in the SGD-treated group. SGD could effectively alleviate the cancerous pain of bone metastasis and mitigate the metastasis that cause osteolytic destruction of bone.