The aim of the study - to identify the causes and develop methods of treatment and prevention of septic phlegmons of the lower extremities after combined phlebectomy. The article presents the experience of treating 6 patients between the ages of 21 and 69 years with severe pyo-inflammatory complications (septic phlegmons) of the lower extremities after combined phlebectomy between 2012 and 2019. All patients had signs of a expressed systemic inflammatory response (SIRS3 and SIRS4) when they received admission. Against the background of intensive detoxification therapy in intensive care department, all patients were operated on emergency indications. Under anesthesia, they were performed an opening the subcutaneous phlegmons of the lower extremities using wide stripes incisions. Comprehensive therapy included the prescribing of antibiotics, anti-inflammatory drugs, stage necrectomy, the treatment of purulent wounds with various variants of surgical energy (plasma flows and NO-therapy) in various modes. The results of the treatment were estimated in the near and distant periods. Timely diagnosis, surgical treatment with the opening of purulent cavities with a wide excision of necrotized subcutaneous fat and fascia, as well as the subsequent plasmadynamic stage wound purification in therapeutic mode allowed in all cases to stop systemic inflammatory syndrome, to achieve rapid cleansing and healing of wounds. All patients were discharged for outpatient treatment. There were no fatalities. The long-term results of treatment were found to be satisfactory, and no patients were found to be disabled. The careful compliance to the main stages of the combined phlebectomy, especially the quality control of postoperative hemostasis, can minimize the development of septic complications. The comprehensive treatment with active surgical tactics and the use of air-plasma technologies allow to achieve a rapid cleansing of wounds and a speedy recovery of patients.