Does Carbon Dioxide Therapy Help Horse Wounds Heal?

By Dr Duncan Houston

New wound therapies always sound appealing, especially when you are dealing with a horse wound that refuses to behave.

Carbon dioxide therapy is one of those treatments. The theory sounds promising: expose the wound area to carbon dioxide, improve blood flow and local oxygen delivery, and help tissue repair. In human medicine, CO₂-based approaches have been explored for difficult wounds, so it is understandable that horse owners and vets would ask whether the same idea could help equine limb wounds.

The problem is that horse wounds are not simple. Lower limb wounds in particular are difficult because of movement, skin tension, limited soft tissue, contamination risk, and the tendency to develop proud flesh.

So, does carbon dioxide therapy work for horse wounds? The honest answer is: not clearly enough to call it proven yet.

Quick Answer

Carbon dioxide therapy for horse wounds is an experimental or emerging treatment, not a proven replacement for good wound care. The main controlled horse study found no significant difference in overall healing rate and no improvement in skin graft acceptance compared with room air treatment, although there were some signals that larger wounds may have been smaller during part of the follow-up period. For now, CO₂ therapy should not distract from the basics: proper wound assessment, cleaning, debridement when needed, bandaging, movement control, infection management, tetanus protection, and veterinary monitoring. (The Horse)

What Is Carbon Dioxide Wound Therapy?

Carbon dioxide wound therapy involves exposing tissue to CO₂ with the aim of improving the wound-healing environment.

The proposed theory is that CO₂ may increase local blood flow, influence oxygen release from haemoglobin, and support tissue oxygenation. In wound healing, oxygen delivery matters because cells need oxygen for repair, collagen formation, immune defence, and new blood vessel growth.

That sounds logical, but plausible biology is not the same as clinical proof.

In horses, the important question is not whether CO₂ could theoretically affect tissue. The real question is whether it improves healing in the messy, mobile, contaminated, high-tension wounds we actually see in practice.

At the moment, the answer is still uncertain.

Why Are Horse Wounds So Difficult to Heal?

Horse wounds can be frustrating, especially below the knee or hock.

Lower limb wounds are difficult because there is less soft tissue covering bone, tendons, ligaments, and joints. The skin is often under tension, the limb moves constantly, and wounds are easily contaminated with dirt, bedding, manure, and flies.

Lower limb wounds are also prone to excessive granulation tissue, commonly called proud flesh. Proud flesh develops when the inflammatory phase of wound healing is inefficient or prolonged, and lower limb wounds are more prone because infection, excessive motion, inappropriate bandaging, and anatomy can all interfere with normal repair. (AAEP)

That is why new technology can be tempting. Everyone wants the magic shortcut.

Unfortunately, with horse wounds, the boring basics still do most of the heavy lifting.

What Did the Horse CO₂ Study Show?

The key equine study involved six horses with created wounds on the front limbs. One limb received carbon dioxide therapy for 20 minutes per treatment, while the opposite limb was treated with room air as the control. The horses received 11 treatments over the first 14 days, and skin grafts were placed on the larger wounds on day 7. The wounds were assessed by blinded observers, which is important because it reduces bias. (The Horse)

The main findings were mixed:

• There was no significant difference in the rate of healing between CO₂-treated wounds and room-air-treated wounds.

• There was no improvement in skin graft acceptance with CO₂ therapy.

• Wound assessment ratings and pathology scores did not clearly favour CO₂.

• Some treated large wounds were smaller during part of the post-treatment period, which suggests a possible signal worth studying further.

• The study did not follow the large wounds all the way to complete healing, so it could not prove whether CO₂ wounds would have closed earlier in the end. (The Horse)

So the fair takeaway is not “CO₂ therapy definitely does not work.”

The fair takeaway is: current horse-specific evidence does not show a strong enough benefit to treat CO₂ therapy as proven wound care.

Is Carbon Dioxide Therapy Worth Trying?

Maybe in selected cases, but not as a first-line solution and not as a substitute for proper wound management.

A horse with a serious wound does not need a gadget first. They need a diagnosis.

Before considering CO₂ therapy, the important questions are:

• Is a joint, tendon sheath, tendon, ligament, bone, or body cavity involved?

• Is the wound infected?

• Is there devitalised tissue that needs debridement?

• Can the wound be closed?

• Does it need to heal by second intention?

• Is movement preventing healing?

• Is the bandage helping or causing problems?

• Is proud flesh developing?

• Is tetanus protection current?

If those questions have not been answered, CO₂ therapy is just expensive fog around an unsolved problem.

In practice, I would think of CO₂ therapy as an adjunct that still needs more evidence, not as the main event.

How Worried Should You Be About a Horse Wound?

Some wounds are minor. Others look small but are dangerous because of where they are.

The real danger with horse wounds is not always size. A small puncture near a joint can be far more serious than a dramatic-looking skin flap in a safer location.

When Is This an Emergency?

Treat a horse wound as urgent if there is any chance a deeper structure is involved.

Call your vet immediately if the wound is:

• Near a joint

• Near a tendon sheath

• Over a tendon or ligament

• A puncture wound

• Deep or gaping

• Heavily contaminated

• Bleeding heavily

• Associated with severe lameness

• Showing visible bone, tendon, or joint fluid

• On the chest, abdomen, eye, or face

• Causing rapidly increasing swelling

• Producing pus, bad smell, heat, or worsening pain

• Not improving over several days

• Developing proud flesh

• Associated with fever, depression, or reduced appetite

Merck Veterinary Manual notes that wounds over joints, tendon sheaths, tendons, puncture wounds, and wounds exposing or penetrating bone should be thoroughly assessed for deeper structure involvement. Referral may be needed for tendon injury, synovial penetration, extensive degloving injury, severe blood loss, neurological signs, or thoracic or abdominal involvement. (MSD Veterinary Manual)

This is where waiting can be costly. A joint infection missed early can become career-ending or life-threatening.

What Should You Do Right Now?

If your horse has a fresh wound, focus on safe first aid and avoiding harm.

1. Move the horse to a safe area.
   Prevent further injury and keep the horse calm.

2. Control bleeding with pressure.
   Use a clean towel or dressing and firm pressure. Do not keep removing the dressing to check.

3. Do not apply harsh chemicals.
   Avoid caustic powders, strong disinfectants, motor oil, bleach, or mystery “old-timer” mixtures.

4. Protect the wound from dirt and flies.
   A clean, non-stick dressing and appropriate bandage can help until the vet sees it.

5. Do not probe deep wounds yourself.
   You can introduce contamination or damage tissue.

6. Call your vet if the wound is deep, near a joint, below the knee or hock, contaminated, or associated with lameness.

7. Check tetanus status.
   Tetanus prevention is a core part of wound care in horses.

Merck’s wound treatment principles include assessing severity, cleaning and preparing the site, debridement when needed, bandaging, antimicrobials when appropriate, pain management, and tetanus prophylaxis. (Merck Veterinary Manual)

The best early wound care is not dramatic. It is clean, calm, protective, and prompt.

How Do Vets Decide How to Treat a Horse Wound?

A vet is not just looking at the skin.

They are trying to answer several important questions:

• How deep is the wound?

• Is anything vital exposed or damaged?

• Is there joint or tendon sheath involvement?

• Is there a foreign body?

• Is the tissue still healthy enough to close?

• Does the wound need debridement?

• Can it be sutured now, closed later, grafted, or left to heal open?

• How much movement will affect healing?

• What bandage or immobilisation is needed?

• Does the horse need antibiotics, pain relief, or tetanus protection?

Fresh, clean wounds may sometimes be closed primarily. Contaminated wounds, wounds with tissue loss, or wounds that cannot be fully cleaned may need delayed closure or second-intention healing. (Merck Veterinary Manual)

That decision matters far more than whether a trendy therapy is added later.

What About Proud Flesh?

Proud flesh is one of the biggest complications of horse limb wounds.

Granulation tissue is normal at first. It fills the wound bed and supports healing. Proud flesh is when that granulation tissue becomes excessive and rises above the skin edges, preventing the wound from closing properly.

Proud flesh is more likely when there is:

• Excessive movement

• Infection

• Poor bandaging

• Delayed veterinary care

• Lower limb location

• Large open wounds

• Repeated trauma to the wound

• Ongoing inflammation

AAEP notes that early veterinary intervention and appropriate wound care are important for preventing complications, and treatment may include topical medication, debridement, bandaging, and in some large or refractory wounds, skin grafting. (AAEP)

The mistake owners often make is waiting until proud flesh is large, bulky, and established. It is usually easier to prevent than to fix.

Could CO₂ Therapy Help Proud Flesh?

At the moment, there is no strong evidence that CO₂ therapy reliably prevents proud flesh in horses.

In the controlled study, CO₂ therapy did not clearly improve wound assessment ratings or pathology, and there was not a convincing overall healing advantage compared with room air. The study did find some possible differences in wound size during part of the follow-up period, but that is not enough to say CO₂ prevents proud flesh or should replace standard wound management. (The Horse)

If proud flesh is the problem, the priority is still:

• Reduce motion

• Control infection

• Use appropriate bandaging

• Debride excessive granulation tissue when needed

• Protect the wound

• Reassess frequently

CO₂ may be interesting research territory, but proud flesh still needs old-fashioned veterinary discipline.

Proven Ways to Support Horse Wound Healing

The best wound outcomes usually come from doing the basics well and early.

Useful wound-healing principles include:

• Early veterinary assessment for significant wounds

• Proper cleaning and lavage

• Careful debridement of dead or contaminated tissue

• Appropriate closure when suitable

• Bandaging below the knee or hock when indicated

• Movement control

• Tetanus protection

• Pain relief when needed

• Antibiotics only when clinically appropriate

• Fly control

• Clean bedding or turnout management

• Regular reassessment

• Early management of proud flesh

• Skin grafting for selected large or slow-healing wounds

Bandaging can protect wounds from contamination and insects, support tissue, reduce swelling, and provide stability, but it must be applied correctly. Bandages that are too tight, too loose, wrinkled, dirty, or left unchanged for too long can create new problems. (The Horse)

This is where experienced veterinary and nursing care is worth far more than a cupboard full of wound products.

What About Skin Grafting?

Skin grafting can be useful for large wounds, especially those that are slow to close or at high risk of excessive scarring.

In the CO₂ study, skin grafts were placed on the larger wounds on day 7, but CO₂ therapy did not improve graft acceptance compared with room air. Graft acceptance was high in both groups, but not better in the CO₂-treated wounds. (The Horse)

That matters because it suggests CO₂ therapy should not be promoted as a proven way to improve graft success in horses.

Skin grafting itself can still be valuable. The key is case selection, recipient bed preparation, infection control, bandaging, motion control, and follow-up.

What Should You Ask Before Paying for CO₂ Therapy?

Before using any advanced wound therapy, ask practical questions.

• What diagnosis are we treating?

• What is the goal of CO₂ therapy in this specific wound?

• What evidence supports it in horses?

• What standard treatments have already been done?

• Is infection controlled?

• Is proud flesh controlled?

• Is the bandage plan correct?

• Could this wound need imaging, surgery, closure, or grafting instead?

• How will improvement be measured?

• What will we do if the wound is not better in 7 to 14 days?

The goal is not to reject new technology automatically. The goal is to avoid using new technology as a distraction from fundamentals.

A treatment should earn its place in the plan.

Common Mistakes Owners Make

Waiting too long to call the vet
A wound near a joint, tendon sheath, tendon, eye, chest, abdomen, or deep structure needs prompt assessment.

Assuming a small puncture is minor
Small punctures can track deep and seal over, trapping infection.

Over-cleaning the wound
Repeated scrubbing can damage fragile new healing tissue.

Using harsh topical products
Strong chemicals and caustic powders can delay healing.

Letting proud flesh get ahead
Once granulation tissue rises above the skin edges, closure becomes harder.

Bandaging badly
Poor bandaging can slip, rub, trap moisture, cut off circulation, or worsen swelling.

Chasing experimental therapies too early
Advanced treatments should support a good wound plan, not replace one.

How To Reduce the Risk of Slow Healing

Not every wound can be prevented, but many complications can be reduced.

Helpful prevention and management steps include:

• Remove sharp wire, metal, broken boards, and protruding nails from paddocks and stables

• Keep fencing safe and visible

• Use safe turnout groups where possible

• Check legs daily, especially after turnout or transport

• Keep tetanus vaccination current

• Control flies

• Manage mud and manure exposure

• Keep bandages clean and dry

• Follow wound recheck instructions

• Limit movement when your vet recommends it

• Photograph wounds regularly to track progress

• Call early if swelling, heat, smell, pus, lameness, or proud flesh develops

With wounds, the horse owner’s biggest advantage is early pattern recognition.

A wound that is smaller, cleaner, less swollen, less painful, and steadily filling from the bottom is usually moving in the right direction.

A wound that smells, swells, bleeds easily, grows proud flesh, becomes more painful, or stops shrinking needs reassessment.

FAQs

Does carbon dioxide therapy heal horse wounds faster?

Current horse-specific evidence does not clearly prove that CO₂ therapy makes wounds heal faster. One controlled study found no significant difference in overall healing rate compared with room air treatment, although some treated large wounds were smaller during part of the follow-up period. More research is needed before it can be called a proven therapy. (The Horse)

Is CO₂ therapy harmful to horse wounds?

The available study did not show major obvious harm, but that does not mean it is automatically useful or appropriate for every wound. The bigger risk is relying on an unproven therapy while delaying proper wound assessment, debridement, bandaging, infection control, or surgery.

What is the best treatment for proud flesh?

Proud flesh often needs veterinary management. Treatment may include reducing movement, proper bandaging, topical medication in selected cases, and trimming excessive granulation tissue level with the surrounding skin. Large or chronic wounds may sometimes need advanced techniques such as grafting. (AAEP)

When should a horse wound be seen by a vet?

Call your vet for deep wounds, punctures, wounds near joints or tendon sheaths, wounds below the knee or hock with swelling or lameness, contaminated wounds, wounds with visible tendon or bone, heavy bleeding, fever, or any wound that is not clearly improving.

Can I just leave a horse wound open to heal?

Some wounds do heal by second intention, meaning they heal open rather than being stitched closed. However, this should still be managed carefully. Lower limb wounds are prone to contamination, motion, slow healing, and proud flesh, so veterinary guidance is usually worth it.

Final Thoughts

Carbon dioxide therapy is interesting, but interesting is not the same as proven.

The current equine evidence does not support CO₂ therapy as a reliable shortcut for horse wound healing, proud flesh prevention, or skin graft success. It may deserve more research, especially in different wound types, but it should not replace the fundamentals.

For most horse wounds, the best outcomes still come from early assessment, clean wound care, correct bandaging, movement control, infection control, tetanus protection, and close follow-up.

The real question is not “what new therapy can we try?”
It is: has this wound been properly assessed, protected, and managed from the start?

That is still where the biggest difference is made.

If you are unsure whether your horse’s wound needs urgent care, whether proud flesh is developing, or whether an advanced therapy is worth considering, ASK A VET™ can help you decide what to do next.