The medical use of ozone intraarterially, subcutaneously, intramuscularly and externally and in autohaemotransfusion or as a gas introduced into body cavities, as well as drops, compresses or liquids for rinsing etc. brings about very good therapeutic results. Ozone exerts a positive effect on oxygen and nutrient supply of cells, it enhances immunological processes, inhibits inflammatory processes, has a bacterio-, fungi- and virusostatic action when there is impaired resistance to microorganisms, improves rheological properties of the blood and exhibits no side effects in patients. Consequently ozonotherapy may be regarded asan effective method of treatment.