Ozone is an allotrope of oxygen, widely known to exert an anti-oxidant potential. The ability of low, controlled and standardized doses of ozone in the ozone adjunct treatment of bacterial infections, which occur in wounds, is engaging clinical research to deepen the role of ozone in eradicating even multidrug-resistant bacteria. Ozone activates the nuclear factor erythroid 2-related factor 2 (Nrf2), and this activation triggers a complex cascade of events, which ultimately leads to macrophage training and an improvement in their ability to operate a clearance of bacteria in the patient’s anatomical districts. In this review, we try to elucidate the recent evidence about the mechanisms with which ozone can actually remove bacteria and even multi-drug-resistant (MDR) bacteria, accounting on its complex ability in modulating immunity.

Background. Ozone is an allotrope of oxygen whose use in medicine has rapidly grown in recent years. Ozonated blood allows for the use of ozone in a safe modality, as plasma and blood cells are endowed with an antioxidant system able to quench ozone’s pro-oxidant property and to elicit the Nrf2/Kwap1/ARE pathway. Methods. We present two clinical studies, a case-series (six patients) observational study adopting ozone as a major autohemotherapy and topical ozone to address infected post-surgical wounds with multi-drug resistant bacteria and an observational study (250 patients) using ozonated blood for treating knee osteoarthritis. Results. Ozonated blood via major autohemotherapy reduced the extent of infections in wounds, reduced the inflammatory biomarkers by more than 75% and improved patients’ QoL, whereas ozonated blood via minor autohemotherapy improved significantly (p < 0.001) WOMAC and Lequesne’s parameters in knee osteoarthritis. Conclusions. The models described, i.e., ozone autohemotherapy in wound antimicrobial treatment and ozonated blood in knee osteoarthrosis, following our protocols, share the outstanding ability of ozone to modulate the innate immune response and address bacterial clearance as well as inflammation and pain.

(1) Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic syndrome characterized by fatigue as its major and most outstanding symptom. Previous evidence has supported the ability of ozone to relief ME/CFS related fatigue in affected patients (2) Methods: A number of 200 ME/CFS previously diagnosed patients, (mean age 33 ± 13 SD years) were consecutively treated with oxygen-ozone autohemotherapy (O₂-O₃-AHT). Fatigue was evaluated via an FSS 7-scoring questionnaire before and following 30 days after treatment. (3) Results: Almost half (43.5%) of the treated patients evolved their FSS scale from the worst (7) to the best (1) score, assessing the highest improvement from being treated with O₂-O₃-AHT. Furthermore 77.5% of patients experienced significant ameliorations of fatigue, of 4–6 delta score. No patient showed side effects, yet experienced long lasting fatigue disappearance, by three months follow up (4) Conclusions: Treatment with O₂-O₃-AHT greatly improves ME/CFS related fatigue, aside from sex and age distribution.

Acquired antibiotic resistance represents one of the main restrictions to an effective antibacterial chemotherapy. The continuous growth of the phenomenon draws a therapeutical problem to eradicate infections. Ozone presents known properties, such as antibacterial, antiviral, anti-fungal, anti-inflammatory, analgesic, immunomodulation, and reactivation of microcirculation. Oxygen-ozone therapy has no collateral effects, it is minimally invasive, it is not painful and it does not cause allergic or toxic reactions or drug-drug interactions. Therefore, oxygen-ozone therapy has proved to be useful to control and run out infections in patients with a noted antimicrobial resistant pathology. We are evaluating the best protocol to treat these pathologies, to obtain the most efficient therapeutical response.

An increasing body of evidence in the literature is reporting the feasibility of using medical ozone as a possible alternative and adjuvant treatment for COVID-19 patients, significantly reducing hospitalization time, pro-inflammatory indicators, and coagulation markers and improving blood oxygenation parameters. In addition to the well-described ability of medical ozone in counteracting oxidative stress through the upregulation of the main anti-oxidant and scavenging enzymes, oxygen–ozone (O₂–O₃) therapy has also proved effective in reducing chronic inflammation and the occurrence of immune thrombosis, two key players involved in COVID-19 exacerbation and severity. As chronic inflammation and oxidative stress are also reported to be among the main drivers of the long sequelae of SARS-CoV2 infection, a rising number of studies is investigating the potential of O₂–O₃ therapy to reduce and/or prevent the wide range of post-COVID (or PASC)-related disorders. This narrative review aims to describe the molecular mechanisms through which medical ozone acts, to summarize the clinical evidence on the use of O₂–O₃ therapy as an alternative and adjuvant COVID-19 treatment, and to discuss the emerging potential of this approach in the context of PASC symptoms, thus offering new insights into effective and safe nonantiviral therapies for the fighting of this devastating pandemic.

(1) Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a syndrome that has fatigue as its major symptom. Evidence suggests that ozone is able to relieve ME/CFS-related fatigue in affected patients. (2) Objective: To evaluate whether differences exist between males and females in ozone therapy outputs in ME/CFS. (3) Methods: In total, 200 patients previously diagnosed with ME/CFS (mean age 33 ± 13 SD years) underwent treatment with oxygen–ozone autohemotherapy (O₂-O₃-AHT). Fatigue was investigated via an FSS 7-scoring questionnaire before and following 1 month after treatment. (4) Results: The Mann-Whitney test (MW test) assessed the significance of this difference (H = 13.8041, p = 0.0002), and female patients showed better outcomes than males. This difference was particularly striking in the youngest age cohort (14–29 years), and a KW test resulted in H = 7.1609, p = 0.007 for the Δ = 28.3% (males = 3.8, females = 5.3). (5) Conclusions: When treated with O₂-O₃-AHT, females respond better than males.