Contraindications for ozone therapy are the following:

- acute and chronic tendency to bleedings;
- thrombocytopenia;
- hyperthyroidism;
- cramps in the anamnesis;
- individual intolerance to ozone;
- blood coagulation disorder;


Ozone should be used most carefully in case of decompensated conditions:

- in decompensated heart insufficiency;
- in severe acute toxication (incl. alcohol);
- in hypoglycemic conditions;
- in extremal sympathicotonic and parasympathicotonic reactions.

After myocardial infarction ozone therapy can be used not earlier than after 6 months, in patients with hemorrhagic insult in the anamnesis ozone therapy is not recommended for use.

Numerous clinical investigations have confirmed that ozone therapy if properly indicated, dosed, performed etc. is well-tolerated by patients and very seldom can cause any side effects without inducing any adverse reactions in the human body. During and after the procedure the patients can complain about weakness, slight dizziness, sleepiness that last for a short time. Possible are allergic skin reactions (like nettle rash) to local applications of ozone (very seldom).

Since ozone is used as a medicine, like for any other therapeutic agent you should know precise ozone concentration, total dose and exposure time in order to minimize the toxic effect of ozone on the organism and to increase its therapeutic efficiency. Of great importance is ozone concentration in ozone/oxygen gas mixture. Extremely low ozone concentrations do not produce a toxic effect since radicals have been quickly and completely neutralized, but at the same time they are not always as much effective as necessary. On the other hand, extremely high ozone concentrations induce biological activity, but imply cytotoxicity.