Aim — structural and functional analysis of cells from purulent-necrotic wounds in patients with diabetic foot syndrome undergoing ultrasonic treatment with 0.2% Lavasept solution. Material and methods. It is presented morphological/ultrastructural analysis of wound specimens in 90 (DFS) patients aged 27—80 years with diabetic foot syndrome and purulent-necrotic complications who were hospitalized in the department of wounds and wound infections of the Vishnevsky Institute of Surgery in 2013—2016. Main group consisted of 75 patients, control group — 15 patients. Mean age was 58.4±8.2 years. All patients had diabetes mellitus type II for previous 13±4.5 years. Severity of foot tissue damage was assessed according to Wagner classification (F. Wagner, 1981). 46 (51.1%) patients had Wagner III—IV, 44 (48.9%) patients — Wagner II. Complex treatment included radical surgical management of purulent lesion, surgical revascularization for critical limb ischemia and foot reconstruction at the final stage. Additional measures were complete unloading of the foot, correction of carbohydrate metabolism and concomitant diseases. Topical treatment between surgical stages included dressing with 1.0% betadine solution (once a day). Ultrasonic cavitation was additionally applied in the main group. Electron microscopic examination of specimens was used before treatment, after 3—5 and 7—10 days in order to assess effectiveness of ultrasound cavitation for purulent-necrotic complications of DFS. Results. Ultrasound cavitation with 0.2% Lavasept solution effectively cleans wounds from microbial and cellular detritus, destroys cellular membranes of biofilm-forming microorganisms, prevents their redo development and reinfection of the wound. Effective management of the wounds accelerates reparative processes that allows to perform foot reconstruction early.