It is known that almost any pathology is accompanied by an imbalance of the lipid peroxidation (LPO) and the antioxidant system (AOS), and diseases of the female reproductive system are no exception. Thus, modern therapies of nonspecific vaginitis (NV) should include drugs with an antioxidant effect in the complex treatment, because the role of the LPO-AOS system in the mechanism for the development of NV is great. This problem can be solved by new complex drug with plant material with a wide spectrum of action.Aim. The aim of our research was to study the effect of new vaginal suppositories “Melanizol”, containing metronidazole and tea tree oil on the system of LPO-AOS on a model of nonspecific vaginitis in rats.Materials and methods. The study object was the new vaginal suppositories “Melanizol”. As reference drugs there were taken suppositories “Gravagin” and “Hippophaes oleum suppositories”. The study has been carried out on the model of experimental nonspecific (irritative) vaginitis caused in rats by the mixture of turpentine oil and dimethyl sulfoxide. Blood serum and vaginal tissue were used as the material for the study. Thiobarbituric acid-active products (TBA-AP) were determined as the component of a lipid peroxidation. The catalase (CAT), the superoxide dismutase (SOD) and the reduced glutathione (G-SH) were determined as the component of an antioxidant system.Results and discussion. On the background of experimental vaginitis in serum and in vaginal tissue homogenate in rats, significant changes in indicators of the LPO-AOS were noted. Change of these indicators show a systemic response of the body to pathological changes in the vagina, which is manifested in the depletion of AOS and activation of the LPO. The vaginal suppositories “Melanizol” in the study on the model of nonspecific (irritative) vaginitis in rats showed an antioxidant effect. Suppositories “Melanizol” significantly reduce the level of TBA-AP, interfering with lipid peroxidation processes, and restore the level of G-SH, as well as the activity of SOD and catalase in the blood and in the vaginal homogenate, helping to protect the cell membranes. Suppositories “Melanizol” significantly exceed the reference suppositories “Gravagin” and are not inferior to the reference drug “Hippophaes oleum suppositories” in activity to reduce the level of TBA-AP, and to restore the level of G-SH, as well as restoration the activity of SOD and CAT. Antioxidant activity of vaginal suppositories “Melanizol” can be explained by the presence of tea tree oil and metronidazole in their composition, which is confirmed by literature data.Conclusions. The conducted researches have shown that the new vaginal suppositories “Melanizol” demonstrated antioxidation activity. Results of this experiment allow us to recommend them for the further studies as medication for the treatment of nonspecific vaginitis.