On 7^th day of the experiment, there was an excessive accumulation in serum of lipid peroxidation products, as evidenced by increased concentration diene conjugates (DC) (by 2.20 times; p<0.01) and triene conjugates (TC) (by 1.93 times; p<0.01), respectively, compared with the control group of experimental animals. The later, on the 14^th day of experimental periodontitis model, there was a gradual decline in DC (by 1.53 times; p<0.01) and TC (by 1.52 times; p<0.01) in serum compared a group of animals studied at the 7^th day of the experiment, but these indexis were elevated relatively intact animal group (by 1.44 times: p<0.01 and by 1.26 times, p<0.01, respectively). The data shown increased generation of reactive oxygen species, activation of free radical oxidation of lipids throughout the periods of the inflammatory response  formation, but the most expressive in the peak of inflammation, which corresponded to a more severe clinical picture was in the animals of this group. In the later period of periodontitis development, despite some easing of intensity of lipid peroxidation, while full attenuation process in inflamed periodontal tissues not happened.