Ulcers in Pets

Ulcers in Horses

Ulcers in horses (also known as Equine ulcers) are a common ailment experienced by horses of all types. These can cause the horse serious discomfort and lead to a host of health issues, especially if bleeding occurs.

In this article, I will be going over what causes ulcers in horses, simple measures you can take to help prevent ulcers, and common horse ulcer symptoms and treatments.

What Causes Equine Ulcers?

While we do have a good idea of what contributes to ulcers in horses, it is definitely not a complete picture.

Right now, most researchers agree that the major cause of stomach ulcers in horses is periods of fasting or intermittent feeding. Horses, unlike humans, need to graze as their stomach constantly produces stomach acid. If horses fast for extended periods of time, the pH in their stomach decreases. This is especially the case of daytime and evening fasts; nocturnal fasting does not seem to have as strong of a negative effect on a horse’s stomach (1).

If you do not know, the lower the pH of a solution is, the more acidic it is. If a horse goes without food for long periods of time, the pH of its stomach can drop to harmfully low levels. Researchers of equine ulcers are able to regularly induce them by intermittent fasting protocols (2). As a result, a horse should always have access to food during the day and evening hours.

This is interesting as stomach ulcer symptoms in humans are generally caused by H pylori bacteria. In horses, this is not the case, as most studies are unable to find H pylori or even any Helicobacter types of bacteria colonizing the stomachs of horses (3,4). Occasionally an H-pylori relative turns up in horses but this is rare, especially compared to humans where almost all ulcers are concurrent with H pylori infection.

However, we cannot rule out the possibility that bacteria contribute to ulcers in horses. One study reported that a particular bacterium known as E. fergusonii may be associated with gastric ulcers in horses (4). This is an interesting development and one that requires more research in the future.

Ulcers in horses tend to be chronic and come and go frequently, even with treatment, over the course of a horse’s lifetime. If further research unveils a specific bacteria which may be causing these ulcers, then the efficacy of equine ulcer treatment should increase as well.

Symptoms, Diagnosis and Treatment of Equine Ulcers

As a horse cannot speak, the symptoms of horse ulcers are hard to identify. Generally, the most common symptom is colic (abdominal pain), along with loss of appetite, weight loss, and sluggishness. However, some horses will have no symptoms at all.

Equine ulcers are diagnosed by a veterinarian performing an endoscopy. This is a fairly inexpensive procedure and involves navigating a camera into the horses stomach (via the mouth) to check for ulceration. The horse is sedated for this process. Endoscopy is fairly inexpensive and most vets will be able to perform this procedure; do not assume your horse has an ulcer and begin treatment and instead let a veterinarian examine your animal.

Equine ulcers are usually treated with proton-pump inhibitors, much like humans. Humans receive these in pill-form whereas horses typically receive injections. Proton-pump inhibitors reduce the secretion of stomach acid and promote ulcer healing.

As research advances, hopefully we will get a clearer insight into what other factors can influence the formation of ulcers in horses. These advances will be key in developing new treatments for combating the prevalence of equine ulcers.


1. Husted L, Sanchez LC, Baptiste KE, Olsen SN. Effect of a feed/fast protocol on pH in the proximal equine stomach. Equine Vet J. 2009 Sep;41(7):658-62.

2. Morrissey NK, Bellenger CR, Ryan MT, Baird AW. Cyclooxygenase-2 mRNA expression in equine nonglandular and glandular gastric mucosal biopsy specimens obtained before and after induction of gastric ulceration via intermittent feed deprivation. Am J Vet Res. 2010 Nov;71(11):1312-20.

3. Martineau H, Thompson H, Taylor D. Pathology of gastritis and gastric ulceration in the horse. Part 1: range of lesions present in 21 mature individuals. Equine Vet J. 2009 Sep;41(7):638-44.

4. Husted L, Jensen TK, Olsen SN, Mølbak L. Examination of equine glandular stomach lesions for bacteria, including Helicobacter spp by fluorescence in situ hybridisation. BMC Microbiol. 2010 Mar 19;10:84.

Stomach Ulcers in Dogs

Much like in humans, ulcers are a common cause of discomfort in canines. However, the similarities end there as stomach ulcers in dogs are quite different from those in humans.

Stomach Ulcers in Dogs

An ulcer, for those unaware, is an erosion of gastrointestinal lining caused by a variety of things. This erosion is like an open sore which is constantly irritated by stomach acid and digestive enzymes.

Dog ulcers vary in severity, shape, and size. Ulcers range from small ulcers resulting in mild discomfort or large ulcers resulting in internal bleeding and potentially death.

Dog Stomach Ulcer Symptoms

Unlike humans, dogs cannot describe their symptoms. Some stomach ulcer symptoms in dogs to look out for include:

  • Vomiting, especially if blood appears in vomit (occasionally red but frequently black)
  • Loss of appetite
  • Weight Loss
  • Bloody stool (generally black with the appearance of tar)

If your dog experiences any of these symptoms he should be examined by a veterinarian. Examination is necessary as there are a multitude of dog illnesses which could also cause similar symptoms. A proper diagnosis can only be achieved through further testing.

Cause of Stomach Ulcers in Dogs

The majority of ulcers in humans are caused by the bacterium H pylori. However, in dogs, this is not the case. H pylori does not colonize dogs.

However, relatives of H pylori have been recently found to colonize the digestive tracts of dogs, but it is unclear how this bacteria influences ulcer formation. It is thought to play a role in the formation of ulcers but the extent of which is unknown.

The role of bacteria in the formation of ulcers in dogs is an area that needs more research. Ulcers in dogs have only recently begun being diagnosed, so the research just is not there to say conclusively whether these relatives of H pylori cause most dog ulcers or not.

The primary cause of ulcers in dogs is actually thought to be NSAIDs and corticosteroids. These drugs are typically prescribed for dogs with chronic inflammation. The most common reason is arthritis of varying types, but these drugs are also prescribed for drugs with breathing difficulties (bronchitis) and other conditions.

The use of these NSAIDs (ibuprofen, aspirin, naproxen) and corticosteroids can lead to ulceration over time. Due to differences in gastric physiology, canines are more susceptible to the negative effects of these drugs than humans are (at least in terms of ulcers).

The result is that canines get ulcers of the stomach (gastric ulcers) as their most common type of ulcer, whereas humans are more likely to get ulcers in the initial part of the small intestine (duodenal ulcers).

Due to high risk for ulceration, many vets prefer that dogs be given these types of medications on an as needed basis, every other day, or recommend cutting pills to find the smallest dose required for the condition.

On the other hand, many dog owners mistakenly self-medicate their animals with aspirin and ibuprofen when their dog is experiencing joint pain. This can be a mistake due to high risk for ulceration. Be sure to allow your veterinarian to decide your animal’s treatment procedure.

If your dog experiences any dog ulcer symptoms and is regularly taking NSAIDs or other medications, bring up these side effects to your vet as soon as you can. It is much easier to treat an ulcer in the early stages than it is after it advances.

Dog Ulcer Treatment

Once diagnosed, ulcers in dogs are treated much like ulcers in humans, typically with a proton-pump inhibitor. This is typically omezaprole (available over the counter and known as Priolosec). In the future when more is known about the relationship of bacteria and ulcers in dogs, perhaps antibiotics will be added as well.

We strongly recommend not trying to medicate your dog but rather let your veterinarian decide if PPIs are appropriate and if so what dosage to take. Dogs do not dose the same way as humans. Additionally, you can often save money by going to the veterinarian as veterinarians often have much cheaper medicine than the local pharmacy.