Equine Gastric Ulcer Syndrome (EGUS) describes ulceration of the lining of the oesophagus, stomach and duodenum in horses.

Ulcers are highly prevalent in foals, mature horses and performance horses. Studies have found 80-90% of racehorses and up to 60% of performance horses are affected.

Why do Horses get EGUS?

Digestive system of a horse functionality

Horses produce gastric acid to break down ingested food. Adult horses produce around 1.5 litres (0.4gallons) of stomach fluid per hour. Even when horses are fasting, their bodies continue to produce gastric acid.

Ulcers occur when the lining of the oesophagus, stomach and duodenum are over exposed to gastric acid.

Diet and Lifestyle

Equine ulcers are a man-made problem.

The domestication of horses has led to diet and lifestyle changes that leave them prone to gastric ulceration.

Horses are natural grazers - they usually spend up to 17 hours a day eating. While they're eating, the horse's stomach acidity stays relatively low as both saliva and the ingested food help to neutralise the acid.

However, the horse produces stomach acid even when they're not eating. This means that acid will accumulate in the stomach.

Equine probiotics have become more popular as a horse supplement.
Feed digests in foregut - ferments in hindgut

Stabled horses are more prone to ulcers as they are often fed larger meals, once to twice per day - and have limited access to pasture.

Free grazing/high roughage diets can prevent ulcers due to the constant ingestion of food and high production of saliva.


 What are the Signs and Symptoms of EGUS?

The symptoms can be wide and varied, often presenting similarly to other equine diseases. Many horses with gastric ulcers also do not display any outward signs of the problem.

Clinical signs and symptoms of ulcers can include;

  • Poor appetite
  • Weight loss
  • Poor condition
  • Rough coat
  • Poor performance
  • Behavioural changes
  • Colic


Endoscopic examinations are often needed to officially diagnose EGUS, however, this is often an expensive procedure. An alternative is to check for symptoms using this technique.

In addition, owners that arent able to get an endoscope can make a diagnosis based on response to treatment with ulcer medication.

Signs of improvement are visible as quick as 3 to 4 days after first treating.

Ulcer Treatment for Horses

There are various medications available for the treatment and prevention of EGUS. Most of which either help to buffer or neutralise the gastric acid or assist in controlling its secretion.

Horse Ulcer Medication

Omeprazole the approved ‘proton pump inhibitor’ (PPI) which controls gastric acid secretion. This prevents ulcers and allows existing ulcers time to heal without increased acid exposure. Ideal medication for use as both a treatment and as a preventative in smaller doses.

Recommended treatment regime is once-a-day for 28 days. Administration is in three different forms (tablet, paste and granules) which should suit even the fussiest of horses.

Sucralfate is both a treatment and preventative. Sucralfate forms a sticky gel which coats the sites of the ulcers. This barrier protects the ulcer from further acid production during digestion and allows it to heal.

Sucralfate is best used in conjunction with omeprazole. For best results administer up to 3 times per day.

Preventing Equine Gastric Ulcer Syndrome (EGUS)

Eliminate the negative factors

The first factor in preventing ulcer recurrence is by changing the horse’s diet and lifestyle. The most important change is to increase a horse’s access to roughage. In addition,  high grain diets can contribute to ulcers, so always ensure you are following guidelines and not over feeding.

How to cure Equine Gastric Ulcer Syndrome

Is there really a cure for ulcers in horses?

Understand that horses naturally produce stomach acid 24/7.  The cure is in controlling the production of acid in a combination of a good diet and administering gastric ulcer medication. Ulcers can take several weeks to heal. It is very common for horses to get them again and again. Be vigilant and observe any behavioural changes, then respond accordingly through a change in diet and medication.

Long-term use of gastric ulcer medication (Omeprazole - PPIs) indicates no known serious side effects. However, it's best to discuss long term use with your local vet.

In conclusion, the best practice to treat and prevent Equine Gastric Ulcer Syndrome is through medication and dietary changes.