Objective: Metronidazole is a nitroimidazole derivative antibiotic that has been used against protozoa and anaerobic organisms for a long time. Furthermore, it has been used in non-infectious inflammatory diseases such as acne, Crohn’s disease, periorificial dermatitis, rosacea and seborrheic dermatitis recently. However, the studies about this issue are very few and its mechanism of action is unknown. The aim of our study is to evaluate the possible anti-inflammatory activity of metronidazole in vivo by using the mice- carrageenan-induced paw edema method. Material and Method: Mice were administered a single dose of 2, 20 or 200 mg/kg metronidazole via oral gavage. One hour later, 2% carrageenan was injected sub-plantar to the hind paws. The paw thickness of mice was measured just before the carrageenan injection and at 1, 2, 3, 4, 24 and 48 hours after injection by dial thickness gauge. For comparison, another group of mice received indomethacin (10 mg/kg, orally) used as a reference drug. IL-1β and TNF-α levels in the paws of mice were measured by the ELISA method. ANOVA (post-hoc Bonferroni) and Student’s t tests were used for statistical analysis. Results: Metronidazole displayed equi-potent anti-inflammatory activity with indomethacin in the carrageenan-induced mouse paw edema model. It is shown that less edema occurred at all doses (2, 20 and 200 mg/kg) compared to the control group and no differences were obtained in effect between the doses. It was observed that in metronidazole treated groups, paw thickness returned to baseline values 48 hours after carrageenan injection, unlike the control group. IL-1β and TNF-α levels, which were increased with carrageenan injection, were significantly decreased with metronidazole treatment. Conclusions: In our study, metronidazole was found to be antiinflammatory due to its effects on relieving edema and reducing proinflammatory cytokines in the paws of carrageenan-induced mice. The effectiveness of metronidazole in treating various non-infectious diseases in recent years may be due to its anti-inflammatory activity.