Abstract: Objective To discuss and analyze the effects of oxidized regenerated cellulose（Surgicel）which was packed in tooth extraction sockets on reducing the risks of postoperative hemorrhage after tooth extraction, without interrupting the therapy of patients taking longterm oral Warfarin. Methods 100 patients taking longterm oral Warfarin were selected and randomly divided into the experimental group and the control group. Surgicel was packed inside the extraction socket in the experimental group, while absorbable gelatin sponge was packed in the control group. The differences of hemorrhage rate after tooth extraction between two groups were analyzed from the perspectives of gender, age, INR, tooth position and the complexity of surgery. Results ①The hemorrhage rate of the experimental group (2%) was significantly lower than that of the control group (16%) (P<0.05); ②There was only 1 case occurring hemorrhage after tooth extraction in the experimental group. The hemorrhage rate of male group after tooth extraction was higher than the female in the control group, but there was no statistically significant difference(P>0.05). The hemorrhage rate of control group after tooth extraction increased with the age and INR(P<0.05); ③There was only 1 case of hemorrhage after tooth extraction in the maxillary molar in the experimental group. In the control group, the hemorrhage rates after tooth extraction were that the molar group was higher than the premolar group which was higher than the front teeth and complicated dental group was higher than simple teeth，and the differences were statistically significant(P< 0.05). Conclusions It is relatively safe to have a simple or complicated tooth extraction for the patients who take longterm oral Warfarin without interruption and whose INR is no more than 3.5. Surgicel can effectively reduce the rate of hemorrhage after tooth extraction in these patients.

Key words: Warfarin, postoperative hemorrhage, oxidized regenerated cellulose