Abstract: Objective To discuss effective precaution of complication after wisdom tooth extraction. Methods 200 patients were randomly divided into experimental group and control group, 100 patients in each. Patients in experimental group took 1 tablet of morphine half an hour before the extraction and received partially injection of dexamethasone on soft tissue and they had one tablet of morphine every night three days later. Patients in control group received the extraction without special therapy. The effectiveness was determined by the extent of tumidity, irritation and the limitation of opening mouth at 24, 48 and 72 hours after the extraction. Results The complications of the patients in experimental group were less than that of the patients in control group. Conclusion It is effective to reduce the complication of tooth extraction by morphine taken orally and received partially injection of dexamethasone on soft tissue before the extraction.