Gastric Ulcers:
Is your horse at risk?

What is Equine Gastric Ulceration Syndrome (EGUS)?

Equine Gastric Ulceration Syndrome (EGUS) occurs when the inner lining of a horse's stomach becomes damaged or ulcerated. Symptoms vary from no obvious signs to severe changes in body condition and poor performance. EGUS may even be life-threatening in foals1

There are two distinct types of EGUS, Equine Squamous Gastric Disease (ESGD) and Equine Glandular Gastric Disease (EGGD) - classified based on their location in the stomach – which can occur alone or as a mixed condition2:

Affected horses

Both types of EGUS can affect any horse or foal. Research reveals it can affect up to2,3:

50% of foals develop gastric ulcers in
the first few months of life.

93% of racehorses
in training2

65% of
performance horses

54% of


There are many risk factors that can lead to an imbalance in your horse's stomach lining.

Unlike humans, who mostly produce stomach acid after eating, horses produce an almost constant flow. This acid is essential to digest food, but it can also cause damage when it comes into contact with the stomach lining.

Horses are equipped to protect themselves against damage via bicarbonate in their saliva and stomach mucus3 and the normal blood supply to the stomach4. However, factors such as intense exercise, stress, a high-grain diet or a reduction in forage feeding can all increase the amount of acid that reaches the lining2,3. In addition, intermittent feeding, transportation and other illnesses can also lead to issues.

Research suggests that the following may
contribute to a type of ulceration:

  • Increased intensity
    of work
  • High grain
  • Long periods
    without foraging
  • Lack of free access
    to water
  • Some types
    of diet


Adult horses

Any or all of the following symptoms may be seen2:

  • Weight loss
  • Poor appetite, fussy eating
  • Dull coat
  • Acute or recurrent colic
  • Behavioural changes
  • Poor performance
  • Crib-biting


Foals may be dull and depressed, and may adopt odd positions or lay on their back to try and relieve the pain of colic1. Other symptoms include:

  • Excess salivation
  • Reduced feeding due to pain
  • Diarrhoea
  • Tooth grinding

Foals may also suffer from 'silent ulcers', meaning they may not outwardly present symptoms until the disease becomes serious 1.


Because of the wide variety of symptoms a horse may present, it is not possible to diagnose EGUS based on clinical signs alone.

The only effective way of diagnosing EGUS is via a Gastrocopy2, a procedure which involves inserting a camera into the stomach using an endoscope. This procedure is usually well-tolerated and takes less than half an hour to complete including time for the horse to be fully awake from its sedation.

Gastric Ulcer Diagnosis

Courtesy of Richard Hepburn, BVSc MS(Hons) CertEM(IntMed) DipACVIM MRCVS.


It is possible to relieve pain, eliminate clinical signs and promote healing using a combination of management changes and medication. Your vet should also aim to prevent recurrence1,2.

Management to reduce risks2

It is prudent to identify known risk factors and take steps to reduce them. This can include:

  • Mimicking natural grazing behaviour by ensuring continuous access to fibrous foods like hay and grass
  • Reducing stress – horses are creatures of habit so a regular routine can help with this
  • Reducing workload while your horse is recovering from significant gastric ulcers – a period of time out from training may be necessary for racehorses
  • Ensuring free access to water during stabling or turn out


In addition to management changes, most horses suffering from established EGUS will also require medication. This may be a short one-off course or a longer medication plan to safeguard against recurrences during stressful periods 2

Is your horse at risk of gastric ulcers?

Does your horse have any of these signs?

  • Poor appetite
  • Poor body condition
  • Weight loss
  • Changes in attitude/ behaviour (including stereotypies)
  • Poor coat condition
  • Signs of colic (especially after feeding)
  • Poor performance

These management factors can also add to the risk of getting gastric ulcers:

  • Reduced turnout
  • Large amounts of concentrate feed
  • High intensity exercise
  • Change in routine
  • Stressful environment
  • Consistent high work load
  • Lack of free access to water
  • Eating straw
  1. Picavet M-Th (2002) Equine Gastric Ulcer Syndrome. Proceedings of the First European Equine Nutrition & Health Congress. February 9. Antwerp Zoo, Belgium.
  2. Sykes et. al. (2015) ECEIM consensus statement: Equine Gastric Ulcer Syndrome in Adult Horses. J Vet Intern Med; 29:1288–1299.
  3. Murray MJ, et al (1990). Prevalence of gastric lesions in foals without signs of gastric disease: an endoscopic survey. Equine Vet J; 22(1):
  4. Bell RJW, et al. NZ Vet Journal 2007; 55(1): 1-12).