OBJECTIVE To evaluate the change in the level of concentration of the antibacterial drug Vancomycin registered in the purulent focus area (facial vein) and in the peripheral blood flow (cubital vein) in patients with phlegmon of the maxillofacial region (MFR). METHODS The clinical material of the study was 12 patients with phlegmon of MFR who were being treated in the maxillofacial department of the N.I. Pirogov State Clinical Hospital No. 1 of the Moscow Medical Center. The drainage of phlegmons was performed on the day of admission of the patient 2-3 days after the onset of the disease. The phlegmons involved two or more spaces of the MFR. As an antimicrobial drug, 500 mg of Vancomycin in 400 ml of saline solution was used intravenously. Quantitative registration of Vancomycin was carried out 2 hours after intravenous infusion. Blood sampling was carried out from the cubital and facial veins in an amount of 7-8 ml intraoperatively at the opening of the phlegmon, under endotracheal anesthesia. The concentration of the antibiotic was determined by high-performance liquid crystal chromatography. CONCLUSIONS The study found that the concentration of Vancomycin in the facial vein exceeds similar indicators obtained from the cubital vein. The difference in the percentage ratio averaged 19.2±7.3%. In 10 patients with phlegmons of various localization, it was found that the penetration of the antibacterial drug into the tissues of the inflammatory focus is higher compared to the periphery. However, in a number of patients, the concentration of the drug did not exceed the minimum suppressive concentration recommended for obtaining a therapeutic effect (for Vancomycin, it is at least 2 mcg / ml). CONCLUSIONS To achieve the therapeutic effect of phlegmon treatment, it is necessary to select an individual dose of the drug for each patient.