Sintoc bark (Cinnamomum sintoc Bl) belongs to Lauraceae (the laurel family). It has been used empirically for a treatment for swelling caused by insects’ bites. In this study, the research examined the analgesic activity and anti-inflammation of essential oil of sintocbark using in vivo methods. The mechanism of anti-inflammation was predicted using molecular docking against COX-2. Essential oil of sintoc bark was collected by distilling through steam distillation, and then analyzed by GC-MS. Analgesic and anti-inflammatory activity was examined by in vivo, which were conducted by writhing and carrageenan-induced methods, respectively. The findings showed that the tested sintoc bark oils contained 36 components of essential oil with eugenol (38.38 %) as a major compound. In the in vivo experiments, sintoc bark oils with doses 0.005 mL, 0.010 mL, and 0.020 mL/20g body weight significantly (p<0.05) reduced the number of writhing of mice when compared to negative control group. All of doses of sintoc bark oils gave significantly affect (confidence level 99 %) compare to negative control. Sintoc oil with dose 0.2 ml/200g had the strongest inhibition compare to positive control (indometasin 10 mg/kg body weight). The molecular docking results indicated that the compounds of aryl propanoid were generally potential to inhibit COX-2.