ozone oxygen mixture conducted from the insufflation outlet 18 via the application set and the reverse flow washing intake 26 is conducted through the reverse flow washing valve 28 to the catalyzer 24 where it is decomposed in fig8 a 8 c the basic implementation of a treatment is illustrated within the framework of a flow chart comprising the steps 8 a through 8 m in step 8 a the device performs a diagnostic routine in which the functioning of the individual system components such as mass flow controller ozone generator ozone analyzer pressure sensors and valves is tested and if applicable initialized once the diagnostics and initialization have been completed in step 8 b treatment can optionally be performed by pressing the key 50 on the touch screen 65 or the adjustment menu can be called up by pressing the key 51 if a treatment sequence is selected in step 8 c the therapy technician is asked to connect the application set for reverse flow washing to the connections and to open the 2 3 way valve the therapy technician then attaches the application set with its intake piece 38 at the insufflation outlet 18 and with the outlet piece 44 at the.