Liquid Ozone Treatments for Wounds: A Systematic Review and Meta-Analysis

Background

Chronic and slow-healing wounds - including diabetic foot ulcers, venous leg ulcers and surgical wounds - place a heavy burden on patients and on health services, and standard care does not always deliver timely healing. Ozone dissolved in water or infused into oils has drawn interest as a topical option because it can reduce bacterial load and may influence the local wound environment. Until recently the evidence had not been gathered and weighed systematically, so it was unclear whether these liquid ozone therapies genuinely improved healing.

Study design

This was a systematic review with meta-analysis of topical liquid ozone therapies - ozonated water and ozonated oils - applied to epithelial wounds in mammals. The authors identified 22 studies for the systematic review: 9 human trials involving 585 participants and 13 animal studies involving 371 animals (rats, mice, guinea pigs and horses). The wound types covered were varied, spanning diabetic foot ulcers, venous leg ulcers, oral and palatal wounds, post-haemorrhoidectomy wounds, tinea pedis (athlete's foot) and experimentally induced skin wounds in animals. Of the 22 studies, 4 provided sufficient comparable data to be pooled quantitatively in a meta-analysis of time to wound healing.

Findings

Across the included studies, wounds treated with topical ozone showed a greater reduction in wound size than comparable wounds given control treatments or standard care. In the pooled analysis, wounds treated with ozonated liquids reached healing roughly one week sooner than controls. The direction of effect was consistent - every study reported some improvement in wound size, healing time or other clinical healing indicators with topical ozone.

What the authors concluded

The authors concluded that topical ozone solutions improve wound healing in mammals and should be considered as part of an overall wound management strategy. They were careful to add that further human trials would be valuable to quantify ozone's specific effects relative to standard treatment, rather than presenting liquid ozone as a replacement for established wound care.

Limitations of this study

Only 4 of the 22 studies contained data suitable for meta-analysis, so the quantitative conclusions rest on a small pooled sample. Combining human and animal studies increased heterogeneity, and nine of the studies carried a high risk of bias, particularly around blinding and outcome assessment. There were also few direct comparisons against modern standard-of-care wound protocols. Taken together, these factors mean the findings are promising but not definitive, and the authors' call for larger, well-controlled human trials is well founded.