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Veterinary protocol
Veterinary Ozone Protocol: Dogs and Cats
Routes, concentrations, volumes and schedules Madrid gives for ozone in dogs and cats: blood, rectal, injection, bagging, ozonated water and oil.
Quick answer: Madrid gives ozone for dogs and cats at 10–35 µg/mL, with a rectal volume of 5 mL/kg. Sessions run 1–2 times a week for 10–20 sessions. The maximum is 35 µg/mL for blood and rectal routes and 40 µg/mL for minor autohemotherapy.
For veterinarians. Ozone use in animals should be done or directed by a licensed veterinarian. This sheet is a reference for them. It is not a guide for treating your own animal and not veterinary advice. Check your licensing board and local rules before using any route.
Concentration10–35 µg/mL
Rectal volume5 mL/kg
Frequency1–2x/week10–20 sessions
Maximum35–40 µg/mL35 blood/rectal · 40 minor AH
What are the basics of ozone therapy in dogs and cats?
- Madrid says veterinary dosing follows body weight and blood volume, and that the principles of the human Declaration apply. The addendum covers animals from 500 g to 60 kg.
- Major autohemotherapy (MAH) in small animals is not done with a bag or bottle. Blood is drawn and ozonated in a syringe, then given back by vein. Minor autohemotherapy (MiAH) gives the blood and gas together into muscle. Rectal insufflation is the simplest route and works as a systemic route in puppies, older animals, cats and small pets.
- Madrid lists three dose levels (low, medium, high). It also lists conditions treated, including digestive, kidney and urinary, skin and ear, eye, mouth, spine and joint problems and, as an add-on, cancer. Evidence is mostly case reports and small trials, so treat the levels as a starting range for the veterinarian, not a prescription.
Sources: Madrid Declaration on Ozone Therapy, 4th edition (ISCO3, 2025), Addendum B (Veterinary Medicine), paraphrased, plus the published studies listed under More detail.
What dose and settings are used for ozone therapy in dogs and cats?
Blood, rectal and injections
Concentrations are in µg/mL (µg/NmL in Madrid). Low, medium and high are the levels Madrid prints in its main veterinary table (Table 4).
| Route | Low | Medium | High | Volume and schedule |
|---|---|---|---|---|
| Major autohemotherapy (MAH) | 10–20 | 20–30 | 30–35 | Collect blood at 1 to 1.3 mL/kg (3.8% citrate 10 mL per 100 mL, or ACD-A) and mix about half gas, half blood. Condition tables list 1 to 1.5 mL/kg. Usually 1 to 2 times a week, 10 to 20 sessions. |
| Minor autohemotherapy (MiAH) | 10–15 | 15–30 | 30–40 | Table 4: 0.1 to 0.2 mL/kg of ozone with 0.1 to 0.5 mL/kg of blood. Section 2.2: blood at 1 mL per 10 kg, no anticoagulant, in a 2 to 10 mL syringe, whole contents into the thigh muscle. The condition tables list a 1 mL syringe for 1 to 5 kg, 2 mL for 5 to 15 kg and 5 mL above 20 kg. 1 to 2 times a week, usually 10 to 20 sessions. |
| Rectal insufflation (RIO3) | 10–15 | 20–25 | 30–35 | 5 mL/kg (50 to 75, 100 to 125 and 150 to 175 µg/kg for low, medium and high). Section 2.3 gives a working range of 10 to 30 µg/mL. Usually 10 to 20 sessions, 1 to 2 times a week; some acute digestive and skin problems list up to 5 times a week. |
| Intra-articular | 8 | 10 | 25 | 0.5 to 10 mL, sized to the joint. The text of section 3.5 gives 5 to 20 µg/mL for joints, paravertebral and trigger points. |
| Paratendon and trigger point | 8 | 10 | 20 | 0.5 to 10 mL. |
| Paravertebral | 5–10 | 10 | 20 | 1 to 10 mL in Table 4. The procedure in section 3.5 gives 0.5 to 3 mL by weight, after 0.5 mL of local anesthetic, with a 19 to 27 G short needle to a depth of 1 to 2 cm. |
| Subcutaneous | 5–10 | 15 | 20 | 1 to 10 mL, anywhere on the skin (dog and cat skin is elastic). Inject slowly. |
| Intralesional | 2.5 to 20 µg/mL, 0.5 to 20 mL, depending on the lesion (section 3.2). In skin disease, small intradermal amounts spread through the lesion. |
Madrid's text and its table do not always match. Where both are shown, use the one that suits the case and stay at the low end first.
Local routes
| Route | Concentration | Volume and time | Notes |
|---|---|---|---|
| Bagging (ozone gas in a sealed bag) | 30–70 µg/mL in the text; Table 4 low 15–30, medium 30–40, high 40–70 | 20 to 30 min. The text also prints a gas flow of 30 to 50 mL/h. | Moisten the skin with double-distilled water first. Seal the bag, remove excess air, add gas slowly, then remove the gas with a vacuum pump. |
| Ozonated water for bladder, vagina or rectum | 10–30 µg/mL in the text; Table 4 low 10–15, medium 20–30, high 30–40 | 20 to 250 mL by weight and problem, given in 2 to 10 mL boluses that are allowed to flow back. Bubble the water 10 to 15 min at 30 L/h. | Use double-distilled water and a silicone catheter. Sedate if the animal is nervous. Never put gas into the bladder, only ozonated water. |
| Vaginal gas after the water wash (vagina only) | 20–30 µg/mL | 5 to 10 min at 20 L/h through a cannula | Given slowly and gently after the ozonated water. |
| Ear (otic) | Gas: 10–25 µg/mL | Rinse with 5 to 50 mL of ozonated double-distilled water, in several flushes with a 2 to 5 mL syringe. Then 2 to 10 mL of gas, left in for 5 min. | Check the eardrum is intact first. Use a silicone probe near the eardrum. |
| Ozonated oil on skin and wounds | Peroxide index (PI) 400 for the granulation phase, 600 for epithelialization, 400–600 for general wounds and minor burns, 800–1200 for badly infected wounds, gingivitis, fungal infection and herpes | Generally once a day | Sunflower and olive oil are used. Sunflower is more stable because it has more double bonds. Use oil made in an industrial generator for pharmaceutical quality. |
What are the best tips when using ozone therapy in dogs and cats?
- Start low and add 5 µg/mL every 2 to 3 sessions for MAH and rectal ozone (Madrid). Base the dose on the animal's condition, lab results, oxidative stress and how long the problem has lasted.
- For rectal insufflation use a female vaginal cannula in dogs or a sterile urethral catheter on a syringe in cats. Lubricate the tip with ultrasound gel or petroleum jelly, as Madrid says.
- Madrid's heart and lung table notes that in cats the rectal route is preferable to MAH. Rectal is also the easy option for puppies, older animals and small pets.
- For MAH, draw blood from the cephalic or saphenous vein with a 21 to 23 G microperfusion needle, use a filter at the syringe tip, rock the syringe gently to mix, and give the blood back slowly through the same vein.
- The ISCO3 small-animal guidelines (cited by the study library) give rectal insufflation at 10 to 35 µg/mL and 3 mL/kg, in cycles of 15 to 32 sessions at 2 to 5 a week, and say concentrations above 40 µg/mL are reported to harm the gut lining. Madrid's table prints 5 mL/kg. The spine study below used 3 mL/kg. Confirm the volume before using the higher figure.
- For spine problems Madrid lists, for example, MAH at 15 to 35 µg/mL (10 to 15 sessions), rectal at 10 to 35 µg/mL and 3 mL/kg (9 to 12 sessions), and paravertebral injection at 10 to 20 µg/mL, 0.5 to 10 mL (10 to 15 sessions, 1 to 2 times a week).
What are the precautions for ozone therapy in dogs and cats, and who should avoid it?
- Dogs and cats: hair removal and a clean site matter more here because the coat holds germs. Consider sedation for injections that hurt.
- Eyes: Madrid's horse section warns that ozonated oil with a high peroxide index can burn and irritate the eye surface.
- Sterility. Madrid asks for maximum sterility. Hair removal is mandatory, because hair carries germs into blood, joints and other tissue. Get signed informed consent from the owner.
- Never let anyone inhale the gas. Madrid says ozone must not be inhaled during any procedure, and calls nasal inhalation absolutely prohibited. Ventilate the room and use a destruct unit or suction where gas is vented.
- Materials. Madrid says to use materials made for each technique: latex-free, and PVC-free for some procedures. Use ozone-resistant (silicone) catheters and silicone-coated syringes.
- Routes Madrid says never to use: nasal inhalation, intra-arterial injection (air embolism), direct intravenous ozone gas, ozonated glucose or Lactated Ringer's by vein, and saline "ozonated" by beating a plastic bag with a syringe (phthalates, uncontrolled dose). It also does not recommend injecting ozonated distilled water into a joint or a vein.
- Go low and slow. For blood and rectal routes Madrid starts low and raises the concentration by 5 µg/mL every 2 to 3 sessions. In animals with chronic disease or high oxidative stress it suggests cofactor and antioxidant supplements and a low-dose lead-in. Inject gas slowly to avoid a vagal reflex, and consider sedation for painful methods.
- Contraindications. Madrid's veterinary addendum does not publish its own list of conditions that rule ozone out, and it gives no pregnancy rule. It states that the principles of the human Declaration apply, so the closest reference is Madrid's human list (section 2.1), shown below. The veterinarian decides animal by animal. Take extra care in a pregnant animal: for people, Madrid advises avoiding ozone in the first trimester and reserves later use for specialists, and the same caution is sensible before any blood, rectal, vaginal or uterine route in a pregnant animal.
- MediSkill does not advise ozonated saline. Madrid also describes ozonated saline (a drip, bladder and wound irrigation, uterine lavage). Those routes and doses are left off this sheet.
Closest reference: Madrid's human contraindications
From the Madrid Declaration on Ozone Therapy, 4th edition (ISCO3, 2025), section 2.1. This list is written for people and is shown as the nearest published reference, not as veterinary guidance.
- Direct inhalation of ozone gas. The fluid lining the lungs has no antioxidants to buffer it, so inhaled ozone is toxic.
- Glucose-6-phosphate dehydrogenase (G6PD) deficiency (favism, acute hemolytic anemia). Madrid lists it as a contraindication and recommends testing, but whether it is absolute is debated. MediSkill protocols start low and go slow; see the contraindications article.
- Toxic hyperthyroidism (severe Graves' disease)
- Thrombocytopenia (platelets under 50,000) and severe coagulation disorders
- Severe cardiovascular instability
- Acute alcohol intoxication
- Recent acute myocardial infarction
- Acute massive hemorrhage
- Convulsive states
- Hemochromatosis
- Patients receiving intravenous copper or iron therapy
More detail
Equipment
- Ozone generator with an ozone-resistant gas path (quartz glass, titanium, silicone) and a way to check the output concentration
- Medical oxygen tank and regulator (not an oxygen concentrator) for any gas given by rectum, vagina, injection or blood
- Latex-free, silicone-coated syringes, silicone catheters and ozone-resistant tubing; ozone destruct unit or good ventilation
- Sterile 21 to 23 G microperfusion needle, 2 to 10 mL and 100 mL syringes, filter for the syringe tip, anticoagulant for MAH
- Ozone-resistant bag with a vacuum pump or destruct line for bagging; double-distilled water for ozonated water
What the studies used
Study doses are listed as printed in each paper. They are not Madrid dosing.
- In 21 dogs with chronic disc disease, rectal ozone (3 mL/kg, 20 to 35 µg/mL) plus paravertebral or subcutaneous injections for 12 weeks improved walking score, spinal pain and quality of life in every dog, and 13 of 21 reached the top walking grade. There was no control group. Two dogs had scar tissue at injection sites and one a 5 cm bruise (Portero 2023).
- In 15 dogs with transmissible venereal tumor on weekly vincristine, ozonated minor autohemotherapy (32 µg/mL, blood 0.5 mL/kg mixed 1:1 with gas) took a mean of 2.4 sessions to remission, against 3.6 for the same procedure without ozone (p = 0.056) and 5.4 for vincristine alone (p = 0.008 vs ozone). It was a small trial (2026 randomized trial).
- In 14 dogs with hip osteoarthritis, one injection of hyaluronic acid mixed with 45 µg/mL ozone gas improved force on the leg more at day 90 than hyaluronic acid alone (31% vs 1%, p = 0.01). Lameness scores did not differ between groups (Frontiers Vet Sci 2020).
- In 50 cats with sporotrichosis on itraconazole, adding ozonized sunflower oil (PI 700, once a day) did not shorten healing: about 29 days in both groups (Open Vet J 2025).
The evidence is thin and mostly case series and small trials of 50 animals or fewer. Madrid's doses come from clinical experience and the cited veterinary reports.
Learn more
Background on the methods: autohemotherapy, rectal ozone, bagging and ozone oil. These articles are written for people, so use them for how the method works, not for animal doses.
Related protocols: Veterinary Ozone Protocol: Horses and Cattle, Veterinary Ozone Protocol: Horse Conditions.
Other veterinary protocols
For veterinarians. Educational reference only, not veterinary advice. Follow your scope of practice and local regulations.