Equine Gastric Ulcer Syndrome (EGUS): FAQ

Discover essential information on Equine Gastric Ulcer Syndrome (EGUS), its causes, diagnosis, treatment, and prevention for your horse's optimal health.

Gastric ulcer treatment and prevention seems to be a topic on every horse person’s mind. You can’t log on to Facebook or open a horse catalog without being bombarded with ads for supplements and feeds. Unfortunately many claims made by the companies are unfounded and inaccurate. Here we will answer some common questions regarding gastric ulcers in horses. With this information you can help make decisions that are the best for you and your horse. 


Why do horses get gastric ulcers?

1. They have a unique stomach design. Horses have two different regions in their stomach: the upper “squamous” region and the lower “glandular” region. The lower glandular region is dark pink and color and contains cells which produce acid and mucous which provides a thick protective layer. The glandular portion secretes acid continuously, even when the horse is not eating.  The upper squamous portion does not produce acid but also does not have any protective mucus. For this reason this area is very sensitive to acid exposure and is prone to ulceration. Horses can develop ulcerations in both of these regions, and they are treated as separate disease processes with different causes and treatments. 


2. They are often managed in conditions that go against their nature.  Horses are designed to roam grasslands, constantly moving and eating small amounts of fibrous roughage. This keeps their stomach full most of the time and provides a buffer for the acid. The action of walking also promotes gastric motility, which helps the stomach empty properly and reduces the time the feed sits. Modern domestic horses will often eat only intermittently and will spend long periods of time contained within a stall. They also eat a diet much higher in concentrated feed with high starch and sugars. 

3. Exercise and splash back. If horses exercise without a stomach full of fibrous material the acid at the bottom of the stomach will splash up against the upper squamous portion of the stomach and cause ulceration. Horses in a consistent exercise program are bouncing, compressing and twisting their stomachs in ways that a wild horse would not. This forces acid against the unprotected squamous section more than it would naturally. 


How common are gastric ulcers?

In 2015, EGUS expert Dr. Benjamin Sykes presented information showing that the rate of squamous gastric ulcers in domesticated horses is approximately 60% compared with 20% in feral horses. A study done on show horses that were trailered to an event showed that 82% of all the horses scoped had gastric ulceration of some degree. 

These statistics show that while horses are naturally predisposed to EGUS, domestication has increased the rate of ulceration and exercise and transportation drive that rate even higher. 


What are the signs of gastric ulcers? 

Horses with gastric ulcers can display a wide range of clinical signs ranging from colic to grumpiness. There is no direct correlation between severity of ulcers and severity of clinical signs. Some horses with ulcers will show no clinical signs at all!. Here are some of the more common clinical signs observed in horses with EGUS:

  • Mild colic after eating feed
  • Reluctance to eat grain 
  • Weight loss/”hard keeper”
  • Sensitivity to the girth/cinch being tightened (“girthy”)
  • General grumpy attitude 
  • Poor performance 
  • Behavior changes 
  • Bruxisim (teeth grinding) 
  • Poor haircoat

Not all horses that display these behaviors will have EGUS, and not all horses with EGUS will display all of these behaviors. The only way to identify the disease is to pursue further diagnostics. 


How do we diagnose gastric ulcers?

The only way to properly diagnose EGUS is with direct visualization via gastroscopy. There are no lab tests or pressure points that can diagnose gastric ulcers. 

A gastroscopy consists of passing a long flexible camera up the horse's nose and down the esophagus and into the stomach. The stomach can be fully examined for any presence of gastric ulceration. Horses will be fasted for 12 hours before the exam to ensure the stomach is completely empty. This is essential for if there is any food in the stomach it will render the exam useless. 

Carrollton Equine offers gastroscopy as a haul-in service. Our state of the art gastroscope provides a large visualizing screen and advanced optics for accurate ulcer identification. 

Gastroscope Services


How do we treat gastric ulcers?

Gastric ulcers can only be healed by increasing the pH of the stomach contents (making it less acidic). The less acidic environment allows the ulcers to heal on their own within several weeks. Since the horse’s stomach is constantly creating acid the medication used must be long acting and effective. The only proven medication for healing gastric ulcers is omeprazole, given as daily Gastrogard. Daily omeprazole dosing is incredibly safe and well tolerated by horses. Typical ulcer treatment consists of daily treatment form 2-4 weeks. 

When administering Gastrogard it is important to give it on an empty stomach to allow the best absorption. The best practice is to give it first thing in the morning, a minimum of 30 minutes before feeding. 

There is another medication called sucralfate which is often prescribed in conjunction with omeprazole. Sucralfate will not affect the acid level of the stomach, but it will bind to the damaged mucosa of the stomach and provide protection while it heals- think of it as a band-aid for ulcers. Sucralfate is very helpful when treating ulcers in the glandular portion of the stomach. (Another reason why a gastroscopy is so important! Ulcers in the squamous region and glandular region can look very similar clinically but will require different treatment protocols.)

Sucralfate and Gastrogard can not be given at the same time as the sucralfate will block absorption of medications. Sucralfate should be given one hour after Gastrogard. 

Medication for ulcer treatment can be purchased at the clinic or on our online pharmacy.



Are all omeprazole products the same?

No they are not!. Gastrogard is the only FDA approved gastric ulcer medication for a reason- it’s the only one that works! While there may be many other products that contain omeprazole, most of them are ineffective for one simple reason: omeprazole is broken down in stomach acid but needs to reach the small intestine to be absorbed. Gastrogard and Ulcergard are the only omeprazole products on the market which have been scientifically proven to heal and prevent both squamous and glandular ulcers. Generic medications do not have an adequate gastric buffer so they ultimately end up being broken down in the stomach and not absorbed. Although they may appear cheaper, remember that the most expensive medication is the one that doesn’t work! 


What's the difference between Ulcergard and Gastrogard?

Gastrogard and Ulcergard are both omeprazole products in a gastric buffer paste. Gastrogard is labeled for gastric ulcer treatment and the tube is dosed by the weight which will provide the effective treatment dose of 4mg/kg of omeprazole. Ulcergard is an ulcer preventative which is recommended for times of high ulcer development risk such as transport, showing, or stall rest. Ulcergard tubes are labeled in doses which will provide 1mg/kg of omeprazole, which has been shown to prevent ulcer formation (but will not treat any active ulcers). Since Ulcergard is not labeled to treat active ulcers, it can be purchased over the counter without a prescription. 


Are we able to prevent gastric ulcers?

Once gastric ulcers are treated, it is important to take steps to prevent their re-formation. If no changes are made, they will likely return in several months and require another round of treatment 

1. Management changes 

Allowing a horse access to pasture as much as possible will reduce stress and allow natural grazing. Constant access to forage is essential for stomach health.  For those horses with metabolic issues that can’t tolerate pasture, they should be allowed access to a dry lot and low sugar forage, such as first cutting hay, through a slow feeder. This will  extend the time it takes for them to eat, reducing boredom and stress. Other management changes to reduce stress include maintaining herd groups as much as possible and feeding horses individually to reduce feed time bullying.

2. Feed changes 

Horses that are prone to ulcers should avoid sugary sweet feeds and grains. For horses that are “easy keepers”, they can be maintained on forage and a ration balancer alone. For horses that require more calories they can be fed a commercial grain low in carbohydrates such as Nutrena SafeChoice or Purina L/S. Adding oil to the diet can also help add calories in a stomach friendly way. Alfalfa is another great addition to prevent ulcers as it has a lot of calcium and protein which can buffer stomach acid. 

3. Supplements 

There are multiple supplements available which are designed to reduce the acidity of the stomach, but the majority of them are too short acting, not potent enough or simply have no effect at all. Some may provide a short acting relief, but they will not reduce the acid for long enough to allow actual healing of the lesion. There are no supplements that can heal gastric ulcers. However, there are some supplements that can help prevent gastric ulcer formation after a horse has been treated with Gastrogard. These include SmartPak SmartGut Ultra and Outlast by Purina. When selecting a gastric supplement be sure to select one that has been proven by research, not just the flashiest one with aggressive advertising. 

4. Change in exercise habits 

Feeding horses a small amount of alfalfa or Purina Outlast immediately before exercising can buffer stomach acid and add a protective “forage mat” which will reduce acid splash from movement. This will reduce the likelihood of ulceration secondary to exercise. There is also research to support that horses who exercise only 5-6 days per week have less gastric ulcers than those who work every day of the week. 



Gastric ulcers are more common than people may think and they can cause a significant impact on a horse’s comfort and athletic performance. The only way to properly diagnose gastric ulcers is with a gastroscopy and the only way to treat gastric ulcers is with an FDA approved omeprazole product, Gastrogard. There are several ways to prevent ulcers but Gastrogard is the only way to treat active ulceration. 

Call us today to discuss the possibility of EGUS in your horse and plan an appointment for gastroscopy! 

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About The Author

Dr. Alyson Waring-Scott

MVB, cVMA, VSMT  |  Equine Veterinarian

I am an Equine Veterinarian at Carrollton Equine and enjoy all aspects of equine medicine. I am especially passionate about dentistry and ophthalmology, and have received advanced training in both of these areas. I am also certified in medical acupuncture and VSMT (chiropractic). 

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