Abstract: Objective To explore the analgesic effect of active ingredients of polygonum multiflorum on bone cancer pain in rats. Methods Specific pathogen-free female Sprague-Dawley rats were randomly divided into 3 groups： blank control group（A group，n=6），modeled as sterile saline group（B group，n=6），and bone cancer pain group（C group，n=24）. Rats in B group were given sterile saline during establishment of model while those in C group were injected with breast cancer cells （walker256） at the upper part of the left hind leg to establish a model with bon cancer pain. Those rats in C group were randomly divided into C1，C2，C3 and C4 groups according to the species of drugs administered intragastrically（n=6）. After successful modeling 14 d，15 d and 16 d，rats in C1~C4 group were intragastrically administered with normal saline（2 mL），tetrahydroxystilbene glucoside（60 mg/mL，2 mL），emodin（60 mg/mL，2 mL） and catechin（60 mg/mL，2 mL） respectively. The pain threshold of left foot in each group was measured before each gavage，30 min after gavage，1h after gavage. Results From the 5th day of feeding in rats with cancer pain model，the mechanical pain threshold in C group was significantly decreased and sclerotin structure were obviously destructed compared with A and B groups（P<0.05），but there were no statistical difference observed on the pain threshold and sclerotin structure between A and B groups. Compared with C1，C3 and C4 group，the mechanical pain threshold at each time point in C2 group was significantly increased（P<0.05）. In the C2 group，pain threshold after 30 min and 1 h of gavage were both signifi-cantly increased than that before gavage（P<0.05）；but the pain threshold after 30 min and 1 h of gavage were similar（P>0.05）. Conclusion Polygonum multiflorum can effectively attenuate bone cancer pain in rats and its active ingredients was tetrahydrox-ystilbene glucoside.  

Key words: Polygonum multiflorum, Bone cancer pain, Tetrahydroxystilbene glucoside, Emodin, Catechin