Benefits of ozone on mortality in patients with COVID-19: A systematic review and meta-analysis

Complement Ther Med. 2023 Mar;72:102907. doi: 10.1016/j.ctim.2022.102907. Epub 2022 Dec 10.


Background: The Coronavirus disease-2019 (COVID-19) pandemic continues, and the death toll continues to surge. Ozone therapy has long been used in the treatment of a variety of infectious diseases, probably through its antioxidant properties and the supply of oxygen to hypoxic tissues. This systematic review and meta-analysis aimed to determine the efficacy of ozone on mortality in patients with COVID-19.

Methods: A systematic search was made of PubMed, Embase, Cochrane Library, and, without language restrictions. Prospective controlled trials on treatment of COVID-19 with ozone, compared with placebo or blank, were reviewed. Studies were pooled to risk ratios (RRs) and weighted mean differences (WMDs), with 95% confidence intervals (CIs).

Results: Eight trials (enrolling 371 participants) met the inclusion criteria. Ozone therapy showed significant effects on mortality (RR 0.38, 95% CI 0.17-0.85; P = 0.02), length of hospital stay (WMD -1.63 days, 95% CI -3.05 to -0.22 days; P = 0.02), and polymerase chain reaction (PCR) positivity (RR 0.07, 95% CI 0.01-0.34; P = 0.001).

Conclusions: Ozone therapy significantly reduced mortality, PCR positivity, and length of stay in hospitalized patients with COVID-19. Ozone therapy should be considered for COVID-19 patients.

Keywords: COVID-19; Meta-analysis; Mortality; Ozone.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Antioxidants
  • COVID-19*
  • Humans
  • Ozone* / therapeutic use
  • Prospective Studies


  • Ozone
  • Antioxidants