PURPOSE : The Purpose of this study was to investigate the anti-inflammatory effect on combination dosage of dexamethasone and naproxen after removal of impacted 3rd molars. We evaluated postoperative pain, swelling, and mouth opening limitation quantitatively. PATIENTS AND METHODS : Removal of an impacted lower third molar was done under local anesthesia with 2% lidocaine to 239 healthy patients. We randomly gave experimental group 1.5mg dexamethasone and 200mg naproxen three times a day for postoperative 2days, and also gave control group 200mg naproxen alone three times a day for postoperative 2days. Swelling and pain were measured by visual analogue scale (VAS). Mouth opening limitation was measured by maximum interincisal opening length. We estimated these measurements in the first and second postoperative days. Differences between experimental and control group were investigated considering age, sex, BMI(body mass index), impacted type, surgical site(right or left), and operation time by independent student T-test. RESULTS : In general, swelling, pain, and mouth opening limitations were significantly reduced (p<0.01) by combination dose of dexamethasone and naproxen in postoperative one day. But there was no difference in pain on the second postoperative day. As variables being considered, in the postoperative pain, there was significant difference between experimental group and control group in only male, little bony removal group, left side extraction group. In case of postoperative swelling, there was no significant differences in male, adolescence, long operating time group (over 20 minutes), medium BMI group and right side extraction group. In case of postoperative mouth opening limitation, there was significant difference between only female and long operating time group (over 20 minutes). CONCLUSION : Variables being considered, postoperative swelling was more reduced by the combination dose of naproxen and dexamethasone than that of naproxen alone after removal of impacted 3rd molars. But there was varoius results in pain and mouth opening limitation.