Objective：To observe the effect of arsenic trioxide to the whole body and local strucｔure following injection into the foramen mentale of rabbits. Methods：0.5 ml arsenic trioxide with different concentrations of 0.1%, 0.05%, 0.025%, and 0.0125%, were injected into foramen mentale.The changes of body appearance, count of white blood cells and pathologic feature were observed. Results：With suitable arsenic trioxide concentration， mentale nerve was permanently damaged，and no side effect on the whole body. Structures around the nerve was not ｓeen damaged. Conclusion：Suitable arsenic trioxide concentration can damage nerve axons permanently, and can not bring side effect to the structure around the nerve and whole body.