In Ukraine, parenteral ozone therapy has been successfully used for many years in the treatment of injuries, poisonings, infectious and non-infectious diseases. Clinical evaluation of the effectiveness of ozone therapy is carried out by doctors based on various approaches and using a wide range of biomarkers. Aim. Analysis of the results of the practical use of parenteral ozone therapy and determination of parameters of its clinical effectiveness in the treatment of patients in the intensive care unit. Materials and Methods. Summarized results of treatment of 144 patients with poisoning, injuries, infectious and somatic diseases, aged 18–72 years, women ‒ 84 (58.3%), men ‒ 60 (41.7%), who underwent a course of parenteral ozone therapy in 2017-2021 in the CNE Kyiv City Clinical Hospital of Emergency Medical Care and ozone therapy rooms of private clinics. Parenteral ozonation of blood was carried out with the help of devices of the "Bozon-N-plus" series following the methodology approved by the Ministry of Health of Ukraine ("Methods of ozone therapy", 2001). The methods of systematic, comparative and statistical analysis were used. Results. All patients were divided into 5 clinical groups based on the nature of their disease: the first group ‒ patients with acute poisoning by substances of suffocating hemotoxic effect; the second group ‒ patients with acute infectious diseases; the third group ‒ patients with chronic non-infectious diseases; the fourth group ‒ patients with purulent wounds; the fifth group ‒ patients with drug addiction. Criteria for evaluating the effectiveness of ozone therapy were used for each clinical group. A total of 1423 medical procedures using ozone were performed. The average course of treatment consisted of 3 to 10 procedures. Among them, 313 procedures of intravenous infusion of ozonated physiological solution (200 ml, ozone dose ‒ 0.48 mg, procedures were performed daily or every other day) were performed. 1110 procedures of intravenous infusion of ozonated autologous blood (200 or ‒ 400 ml of autologous blood, ozone dose ‒ 1.8 or 3.6 mg) were performed. The beginning of the course of autohemotherapy was preceded by a session of intravenous administration of ozonated physiological solution (the first procedure), after which the course of autohemotherapy began, with a frequency of 2-3 times a week. Conclusions. The clinical effectiveness of ozone therapy has been confirmed through a complex dynamic assessment of the patient's condition, which involves the use of subjective assessments (well-being, mood, duration of sleep, severity of pain syndrome, etc.) and objective parameters of the patient (clinical, functional, laboratory indicators, specific biomarkers). Keywords: chemical poisoning, ozone therapy, blood ozonation.