목적: Burning mouth syndrome (BMS) is an intensive chronic oral pain for which no medical or dental cause can be found. Controversy exists about the pathogenesis and effectiveness of medications for the management of BMS. The involvement of free radicals and oxidative stress in related to aging, neurodegenerative disease, and inflammatory diseases became clear. The purpose of this study was to evaluate the clinical effectiveness of N-acetylcysteine (NAC) used to treat BMS. 방법:A total of 84 patients with BMS were divided into three groups Group I (n=18) treated with NAC (200mg twice daily), Group II (n=34) treated with clonazepam (0.25mg twice daily) and Group III (n=32) treated with both NAC and clonazepam. A visual analogue scale (VAS) was used to evaluate the severity of burning sensation at the start of treatment and after 8 weeks of treatment. The changes in symptom were analyzed and compared among three groups. 결과:No patients experienced any adverse effects resulting from treatment at any of the evaluation times. The pain values improved in all three groups after 8 weeks of treatment. The overall success rate of treatment among three groups was 55.6%, 58.9%, and 72.8% respectively. 결론:The NAC was a safe and effective for treating patients with BMS. The combination treatment with NAC and clonazepam showed a greater benefit compared with single therapy. Further studies involving a larger number of patiens and longer duration of ttreatment and follow-up are necessary to determine the true efficacy of different therapies.