Ulcers in Horses – Treatment & Prevention

by | Jun 3, 2023 | Equine First-Aid, Equine Health

For owners of certain breeds of horses, ulcers need no introduction. Breeds that are known for being highly athletic and highly energetic run a high risk of having ulcers, therefore it has become almost a joke that any behavioral or health-related problem in this breed has ulcers as its source. While this humor is used as a joke to alleviate the stress of potential vet bills, it is often true that ulcers are a serious health concern amongst our beloved horses, and their common symptoms and underlying causes are both shockingly common and tragically misdiagnosed.

What Are Ulcers?

Mammals that rely on digestion to get energy from their food (for example, humans and horses) have a stomach that is full of chemicals. The stomach is a muscular sac that is full of digestive enzymes and hydrochloric acid. On its own, hydrochloric acid is one of the most caustic and abrasive chemicals in nature. To protect itself, the stomach produces mucus on the inside lining to coat the walls and prevent the acids and enzymes from destroying the tissue. However, for various reasons, sometimes this protective system doesn’t work out so well. In order for the stomach to be protected, there must be the proper balance of mucus and acid/enzymes within the stomach, leading to a neutral pH between the acidic stomach acid and the basic stomach lining. If the horse’s diet is not timed properly (e.g. if the horse gets a lot of heavy grain and then has no access to hay or grass for many hours at a time) or out of balance nutritionally, or if the horse is under excessive stress, the stomach’s overall pH can become too acidic. When this happens, the hydrochloric acid can burn the stomach lining. These burns are ulcers, and if left neglected, they can burn holes in the stomach itself, allowing the caustic stomach juices to leak into the stomach cavity.
Ulcers can affect the upper portion of the stomach (the squamous region) or the lower (glandular) region. If your horse is exhibiting any of the following symptoms, it is worth it to call your vet to perform a gastroscopy (commonly known as “getting scoped”) to determine where the ulcers are, or if there is another hindgut or parasitic problem at play. They may or may not be associated with colic. For more information on colic, check out our other article here.

What Are Common Symptoms of Ulcers?

If you can imagine acid burning away at your stomach lining, you can imagine how ulcers might feel to your horse. Many horses with ulcers can hold out for a long time with minimal symptoms. On the other hand, many symptoms of ulcers are often interpreted as misbehaviors – cinchiness or girthiness, snapping, bucking, kicking, resistance to going forward, sensitive to being brushed especially on the belly or flanks, hypersensitive to the leg, rushing, resistance to lateral work. Physically, the horse may lose weight or condition, or he may get a duller coat, and you may notice him chewing wood in his stall or paddock. If these behaviors develop suddenly in your horse, especially if there are other lifestyle factors, it may be worth it to have the vet come and give his gut a look-see.

For more information, this video is a great resource:

How Can I Prevent Ulcers?

Some horses are predisposed to ulcers, and some horses will get ulcers even under the best of circumstances. Just like some people have more sensitive stomachs, some horses seem to have a particular predisposition to getting more frequent upset stomachs from ulcers. That said, there are several factors that seem to ameliorate the risk of ulcers.
Horses whose natures are preserved as much as possible tend to suffer less from ulcers, in general. Horses are grazing animals, designed to eat by grazing 18 hours per day and ambling around a large, open area in search of the best grazing and drinking sites. Domesticated horses do best when their lifestyle is as closely matched to this ideal as possible. This means planning their diet so that the majority of their calories comes from forage, and allowing them access to this forage for the maximum amount of time possible per day. Consider a slow-feed hay net or a slow-feed manger in the stall or paddock. This will encourage your horse to eat more slowly for longer. If he gets grain, consider feeding him from a toy such as this one, which encourages a grazing motion while encouraging him to eat more slowly for a longer time. Additionally, many horse owners with ulcer-prone horses feed aloe vera to their horses by mixing it with their feeds, and they say that it helps a lot with preventing new episodes of ulcers coming up. If he chews on wood, spraying a product such as Farnam Chew-Stop on the surface can discourage the chewing.
The schedule of competition horses who stand in a stall or paddock for much of the day, then receive vigorous exercise for an hour of the day, is also not ideal. It is better to allow them to wander in a larger paddock, ideally with a compatible friend, to encourage light exercise and movement throughout the day.

How Can I Treat Ulcers?

If you suspect your horse has ulcers, it is VERY important to get help from the vet first and foremost. Ulcer treatments can be expensive, and worse still, if ulcers are misdiagnosed, the wrong treatment can create other harmful problems while not addressing the harmful problem of the ulcers. Your vet may recommend treating ulcers with the drug omeprazole (whose generic name is UlcerGard), dosage according to the manufacturer’s instructions and the vet’s diagnosis. If your horse has ulcers, has a move or rigorous competition schedule coming up, or has been known to suffer from ulcers in the past, there are several supplements on the market which can help. U-Gard, available as pellets or powder, is excellent for promoting stomach health and minimizing stomach problems that can lead to ulcers. MagnaGard and Purina also make supplements specifically designed for ulcer prevention and gut health. Additionally, as has been mentioned, many owners have added aloe vera or coconut oil to their horse’s feeds and reported diminished ulcer symptoms. The scientific data on the efficacy of these supplements is, however, limited.


Ulcers are an elusive, frustrating problem that oftentimes keep coming back to haunt horse owners who just want to make their beloved horses comfortable. As with everything, maintaining a good relationship with the vet is the most important step, followed closely by the maintenance of a lifestyle that is as close as possible to how the horse was designed to live. If your horse starts to suddenly misbehave, consider ulcers as a possible source of the misbehavior, instead of merely assuming that your horse is stupid or naughty or ornery.

Does your horse show signs of ulcers?

About The Author

<a href="https://www.equiniction.com/author/ani-petrak/" target="_self">Ani Petrak</a>

Ani Petrak

Ani Petrak is a freelance linguist and writer based in the Czech Republic. A lifelong English rider and groom, she has experience showing in dressage, hunter-jumpers, trail, and young horse in-hand competitions. She is currently working with a Grand Prix showjumping and dressage trainer while raising and training her young warmblood gelding for a career in dressage, working equitation, and cross-country hacking.

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