Aim. to study the dynamics of clinical and laboratory parameters of endogenous intoxication and prooxidant and antioxidant blood systems in patients with abdominal sepsis. Material and methods. 57 patients with abdominal sepsis were examined. The inclusion criteria for the study were the presence of a clinic of abdominal sepsis and changes in the parameters of the prooxidant and antioxidant blood systems and blood cytokines. Results. In patients with abdominal sepsis, signs of oxidative damage to lipids and proteins were found, as evidenced by a significant increase in the MDA level up to 5.8 μmol / L, catalase content in erythrocytes 94 mmol / min*gHb, spontaneous NBT test activity up to 95% and a decrease in ceruloplasmin in the blood up to 194 mg / l. With abdominal sepsis, a significant increase in the level of TNF-82.7 pkg/ml, IL-10 to 167.6 pkg/ml, IL-6 to the maximum values in this study up to 286.4 pg/ml and IL to 34 pkg was /ml observed. Conclusion. It was found that in patients with abdominal sepsis there is an increase in lipid peroxidation indicators - malondialdehyde in the blood plasma, the activity of the spontaneous NBT test, depending on the phase of the disease and the presence of complicated forms. Changes in the antioxidant defense of the body in abdominal sepsis are manifested by inhibition of the plasma antioxidant ceruloplasmin with a simultaneous increase in catalase in erythrocytes, depending on the phase of the disease and also on the presence of complicated forms of the disease. As a result of this study, increased production of a complex of both pro-inflammatory and anti-inflammatory cytokines with their rapid and excessive entry into the peripheral blood was revealed.