What Horse Owners Need to Know about Exercise Induced Pulmonary Hemorrhage (EIPH)

What Horse Owners Need to Know about Exercise Induced Pulmonary Hemorrhage (EIPH)

Sad horse

What You Need to Know About Exercise-Induced Pulmonary Hemorrhage

Could your horse be at risk for exercise-induced pulmonary hemorrhage (EIPH)? EIPH primarily affects Thoroughbred and Standardbred race horses but can also occur in any horse that spends time exercising intensely, according to a consensus statement published in the Journal of Veterinary Internal Medicine.

What Is EIPH?

EIPH causes hemorrhages (bleeding) in your horse's lungs when it gallops or participates in other strenuous activities. Intense activity creates pressure that strains your horse's lungs and cause breaks in blood vessels that supply blood to the lungs.

As the breaks heal, they scar over. The scarred area of the lung become less flexible, which means your horse has to work harder to breathe. Once EIPH develops, your horse is likely to experience more hemorrhages in the future. The more often hemorrhages happen, the greater the area of damage in the lungs.

What Causes EIPH?

A vacuum effect occurs every time your horse inhales. The negative pressure created by the effect helps oxygen travel from the nose to the lungs. Once air reaches the lungs, it passes through a thin membrane into small blood vessels in the lungs.

At the same time, pressure increases inside your horse's blood vessels, as the volume of red blood cells rises. The increase in red blood cells makes it easier for extra oxygen to reach every part of your horse's body during exercise. Pressure also rises as the horse's heart works harder.

As pressure builds up, the small blood vessels in the lungs begin to hemorrhage. Over time, the scar tissue caused by the hemorrhages can damage your horse's lungs.

Nose bleeds, frequent swallowing and coughing can be signs of EIPH. An otherwise healthy horse may take longer to recover from a long trail ride or struggle to be competitive during a race. Unfortunately EIPH tends to get worse as your horse get older. Horses can have EIPH even if they don't suffer bloody noses. Instead, the blood may collect in the windpipe where you can't see it.

If your horse has EIPH, you may notice that it chokes after exercise, or you might hear a whistling sound when your horse breathes.

What Can Be Done to Treat or Prevent EIPH?

Treatment options for EIPH include:

  • Salix (Furosemide). This drug decreases stress on the small blood vessels in the lungs and reduces bleeding, according to The Horse. Although Salix can be helpful, many racetracks no longer allow it on race day due to concerns that it could enhance a horse's performance. USA Today reported that as of 2021, horses competing in the Triple Crown could no longer use the drug. Other races across the country have also banned Salix.
  • Nasal Dilators. Nasal dilators work the same way as the breathing strips you use to reduce snoring or make it easier to breathe. A review of alternative therapeutic therapies that appeared in AAEP Proceedings noted that 40 to 50 percent of pulmonary (lung) resistance occurs in the nose. According to the review, nasal breathing strips keep the passages in the nose from collapsing and reduce pressure and airway resistance.
  • Concentrated Equine Serum. Injections of concentrated equine serum may be helpful in reducing inflammation and decreasing mucus and the volume of red and white blood cells, according to the Proceedings review. Horses initially receive daily serum injections for five days, then receive weekly boosters.

Are you worried that your horse may have EIPH? Give us a call to arrange a visit with the equine veterinarian.


NCBI: Journal of Veterinary Internal Medicine: Exercise Induced Pulmonary Hemorrhage in Horses: American College of Veterinary Internal Medicine Consensus Statement, 5-6/2015

The Horse:EIPH: Exercise-Induced Pulmonary Hemorrhage

USA Today: Major Tracks to Ban Race-Day Use of Anti-Bleeding Medication, 4/18/2019

American Association of Equine Practitioners: Review of Alternative Therapies for EIPH


Find us on the map

New Office Hours effective Dec. 1, 2018

Our Regular Schedule - Call for 24 hour emergency service 920-837-7766

Clinic Hours


7:30 am-4:00 pm


7:30 am-4:00 pm


7:30 am-4:00 pm


7:30 am-4:00 pm


7:30 am-4:00 pm






Feedback from our clients

  • ""Excellent and very knowledgeable clinic and staff. Very supportive of area's youth, their projects, and organizations!""
  • ""It's been a pleasure to have Dr. Matt as my vet for the past 21 years. He and the staff at Dairyland have always been kind & helpful.""
  • ""I cannot say enough about them! Very helpful with my potbelly pigs! I am so VERY happy I found them!!! They are so willing to help you and not deplete your bank acct!""
  • "We love you Dr. Matt! You helped Apollo keep his eye sight, you never got frustrated with my 5 million questions, you were very patient and always explained things so we could understand what was going on with him. Your staff is great at returning phone calls and making sure patients get exactly what they need. You have been the best vet ever."
  • "I want to give a huge shout out to Dr Matt Schaefer with Dairyland Veterinary Service. I had been struggling to get weight on Kahlua. She wouldn't eat anything I put in front of her. Dr Matt came out and looked at her and we discussed her attitude and habits. He had a good feeling she had ulcers so he suggested treating her with ulcerguard. I got her on it and she is just 2 days from finishing the 28 day treatment. The change in her is phenomenal. She's put on weight and now looks perfect!
    And "