Written by Karen Pilkington and the CAM-Cancer Consortium.
Updated June 25, 2017

Ozone therapy

Does it work?

Systematic reviews, meta-analyses

No systematic reviews of ozone therapy in relation to cancer have been published. Systematic reviews have been published on other uses, for example, in the field of dentistry and in herniated discs19,20.

Clinical trials

No randomised controlled trials have been conducted to assess the effects of ozone therapy in cancer patients.

An open uncontrolled study of ozone therapy in chemotherapy-resistant cancer patients was initiated in 200318. Preliminary findings revealed that, in patients with a Karnofsky performance score of less than 40% (on a scale of 0 to 100% where 0 represents death and 100% reflects normal activity/function and no evidence of disease), no effect on disease progression was observed. Patients with a Karnofsky score of 70% or less reported an improvement in quality of life after 30-45 treatments. The lack of a control group and subjective nature of the outcome measure prevent definitive conclusions being reached, a point conceded by the researcher.

Results of a pilot, uncontrolled study of ozone therapy for tumour oxygenation were published in 200422. Eighteen patients with metastases or advanced tumours accessible to physical examination were enrolled in the study. All patients had a Karnofsky performance status of > 70%, 15 were male and 14 had head and neck tumours, 2 had gynaecological tumours and 2 had bone metastases in the chest wall. Ozone autohaemotransfusion was administered on 3 alternate days in one week. Tumour oxygenation levels were measured using needle probes. No overall statistically significant change was observed. No adverse effects were recorded. Due to the small sample size and uncontrolled nature of the study, these can only be considered preliminary findings. In addition, the clinical relevance of the observed changes in tumour oxygenation is not entirely clear although tumour hypoxia has been reported to adversely affect prognosis in tumours such as those of the head and neck tumours23,24.

A further controlled study by this research group from Spain focused specifically on patients with advanced head and neck tumours who were undergoing radiotherapy25. Nineteen patients were recruited and studied over a 3 year period. Twelve patients received chemotherapy in addition to radiotherapy while 7 received ozone therapy plus radiotherapy. The two groups were not well-matched as the ozone therapy group was older with greater lymph node involvement. However, no significant difference in overall survival was recorded between the two groups.

Ozone has been investigated for other uses in cancer patients. These include a single case report described intravesical instillation of ozonized water in a patient with progressive radiation-induced haematuria26. Osteonecrosis of the jaw has also been reportedly managed with treatments including ozone in myeloma patients (n=1227 and n=127) as well as a separate series of 10 patients with bone metastases28. Preliminary findings on the effects of ozone by rectal insufflations and/or by local application of ozonized-oil, in small uncontrolled studies in patients (19,17 and 12 respectively) with severe and/or refractory radiation-induced haemorrhagic proctitis or bleeding29,37,38. To date, none of these preliminary findings have been confirmed with randomised controlled trials.


Karen Pilkington, CAM-Cancer Consortium. Ozone therapy [online document]. http://www.cam-cancer.org/The-Summaries/Other-CAM/Ozone-therapy. June 25, 2017.

Document history

Fully updated and revised in June 2017 by Karen Pilkington.
Updated/assessed as up to date by Barbara Wider in September 2013.
Summary first published in October 2012, authored by Karen Pilkington.


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