Objective To study the effect and mechanism of Qizhengxiaotong Emplastrum for relieving cancer pain by using cancer pain model.Methods The model of cancer pain was established in mice with lung or femoral cancer.All mice were divided into the treatment group

control group

model group and blank group.The treatment group was given Qizhengxiaotong Emplastrum（0.75 g/kg）

and the model group and blank group were given normal saline solution（0.5 mL/each）externally for 5 days on 10th day after the establishment of model.The control group was given the intramuscular injection of sulfuric tetrahydropalmatine（6.498 mg/kg）on the 14th day after model established.The pain behaviors including mechanical pain sensitivity and thermal hyperalgesia were measured in mice of all groups after the last drug administration.The X-ray radiography was used in mice on the femurs for the imaging evaluation of bone destruction.The immunohistochemistry method was used to detect the levels of tumor necrosis factorα（TNFα）

endothelin（ET-1）and interluking-1β（IL-1β）in focal skin tissue

and the expressions of positive neurons of the spinal dorsal horn including SP-R

c-fos and GFAP in all goups.Results On the 14th day the percent of paw withdrawal response induced by Von Frey fibers（2g）was decreased significantly in the treatment group compared with that in the model group（P<0.01）.The thermal analgesic latency was prolonged significantly in the treatment group than that in the control group（P<0.01）.The result of X-ray radiography showed that bone destruction alleviated

radiological assessment decreased

and the inflammatory mediators of focal skin tissue and relevant positive neuron expressions reduced significantly.Conclusion Qizhengxiaotong Emplastrum is effective to mouse with cancer pain

and it can relieve pain behaviors and delay bone destruction.The analgesia mechanism may be related to the role played by peripheral and central mechanisms together.