Background: The paper compares the effects of ozone therapy and conventional balneological methods on health condition of patients with obliterative atheromatosis and on serum activity of three lysosomal enzymes.
Material/Methods: Sixty-four patients with lower limb ischaemia in the course of obliterative atheromatosis (without diabetes) were enrolled in the study. Thirty-two patients were treated with ozone administered by intravenous infusions and 30-minute aerosol oxygen-ozone baths. A comparative group was formed of 32 patients treated with traditional balneology. There was also a control group made up of 30 healthy subjects. Ozone therapy as well as traditional balneology were administered daily for the period of 10 days, excluding Saturdays and Sundays. Blood for biochemical analysis was collected from elbow vein in the following time intervals: 24 hours before ozone therapy or classical balneology, one hour after therapy and on the 10th, day of treatment. The activity of cathepsin D, acid phosphatase and arylsulphatase as well as the levels of α-1-antitrypsin (protease inhibitor) were determined in blood serum of patients with obliterative atheromatosis.
Results: In patients who received ozone therapy the activity of analysed lysosomal hydrolases returned to the values typical for healthy subjects. Patients' general condition also improved. The use of traditional balneological methods did not result in any significant change either in the activity of lysosomal hydrolases, the level of a-1-antitrypsin or general condition of patients.
Conclusions: Ozone therapy administered by intravenous infusions and aerosol oxygen-ozone baths of lower extremities yields much better therapeutic results in comparison with classical balneology.

Keywords: Cathepsin D, Acid Phosphatase, obliterative atheromatosis, ozone therapy, arylsulphatase