Ozone therapy in animals: does it work? (Dutch context)
Ozone therapy in animals: what it is, uses, and scientific evidence for dogs and horses under Dutch law.
Short & honest
Ozone therapy has promising antimicrobial and anti-inflammatory properties, but evidence from randomised trials in dogs and horses is largely lacking. Evidence grade: C (weak).
Safety assessment: Caution — conditions and risks
Veterinary review not yet completed
This page is awaiting review by a registered veterinary surgeon. Until then, treat the text as education based on the sources listed — not as a verified veterinary judgement.
What is ozone therapy?
Ozone therapy uses ozone (O₃), an unstable gaseous form of oxygen, as a therapeutic agent. In veterinary medicine, ozone is administered via several routes: as ozonated water, ozonated oil, ozone gas in body cavities or — for systemic applications — intravenously by specially trained physicians. Each administration form has a different mechanism of action and risk profile.
What is it used for?
Veterinary surgeons and alternative practitioners use ozone therapy for various conditions [1][2]:
- Wound care — cleaning of infected or poorly healing wounds
- Chronic otitis (ear infections) in dogs
- Periodontal treatment (gum and jaw problems)
- Intra-articular injections for joint disorders, including in horses
- Support in (viral) infectious diseases
What does the evidence say?
Pre-clinical studies show that ozone kills bacteria, inhibits fungal growth and reduces viral activity. Anti-inflammatory and wound-healing effects have also been observed under laboratory conditions [1]. A narrative review from 2020 and a systematic review from 2026 confirm that these biological mechanisms of action are plausible [1][2].
The problem lies in the translation to the clinic. Controlled clinical trials in dogs and horses are scarce. The vast majority of the evidence comes from case reports and narrative reviews with predominantly positive but scientifically uncertain conclusions. Crucial questions — which concentration, how often, via which route, for which condition — have not been systematically answered [2].
| Aspect | Current status |
|---|---|
| Antimicrobial effect (laboratory) | Demonstrated |
| Clinical efficacy in dogs/horses | Insufficient evidence (RCTs lacking) |
| Standardised protocols | Lacking |
| Safety of local applications | Relatively favourable when performed correctly |
| Safety of systemic applications | Risky without trained personnel |
Ozone therapy is currently not a scientifically supported first-line treatment for any condition in dogs or horses. Its use as monotherapy — separate from an integral veterinary treatment plan — is not scientifically justified.
Safety
Local applications such as ozonated water and ozonated oil have a more favourable safety profile than systemic forms when applied correctly. Nevertheless, for all applications: execution by or under the supervision of a authorised veterinary surgeon is required.
Direct inhalation of ozone gas is acutely dangerous for all animal species and must under no circumstances be applied. At too high concentrations locally, tissue damage may occur instead of healing.
Conclusion
Ozone therapy has biologically plausible mechanisms of action and is used experimentally in veterinary practice. However, the evidence for clinical efficacy in dogs and horses is weak due to a lack of controlled trials and standardised protocols [1][2]. Consider ozone therapy only as an adjunctive measure within a veterinary treatment plan, never as a replacement for proven treatments.
Why this verdict?
The available evidence consists predominantly of narrative reviews, pre-clinical studies and case reports. A systematic review from 2026 [2] analysed 96 studies and confirmed biological mechanisms of action, but identified a structural lack of standardised protocols and RCT evidence specifically in dogs and horses. Consequently, efficacy in clinical practice has not been demonstrated at the level required for first-line treatment.
Interactions with medication
- Combination with strong oxidants (hydrogen peroxide, chlorine) increases risk of tissue damage — do not use concurrently
- Possible interaction with antioxidant supplements (vitamin C, E): ozone oxidises these substances, which may affect the efficacy of both — inform the treating veterinary surgeon
Legal status (Netherlands)
In the Netherlands, ozone therapy falls under reserved procedures when administered via injection or systemic route; performance is permitted only by or under the responsibility of a registered veterinary surgeon (Wet Dieren [Animals Act], art. 4.1).
Sources
- [1] Ozone therapy in veterinary medicine: A review. Research in Veterinary Science, 2020. Narrative review doi:10.1016/j.rvsc.2020.03.026
- [2] Evidence and Clinical Applications of Natural Products in Veterinary Medicine: A Systematic Review of Clinoptilolite, Ozone Therapy, Propolis, and Phytotherapy. Veterinary Sciences (MDPI), 2026. Narrative review doi:10.3390/vetsci13050483