What is Gastroscopy?

Gastroscopy is a painless procedure that allows a trained operator to see live images of your horse’s stomach, using a very long, flexible camera device called an endoscope. When inside the stomach, any ulcers can be seen on a video screen.

Why has my horse been offered a gastroscopy?

Many horses do not show outward signs of EGUS, and some of the outward signs could be attributable to other conditions. Gastroscopy is the only way to get a definitive diagnosis of ulcers, and it also allows the vet to see the severity and extent of any ulceration.

What is involved?

To start, a three-metre long endoscope is passed into the horse’s nostril, and down through the pharynx, larynx and epiglottis into the stomach.

To achieve the optimal angle to access the pharynx, and avoid potential damage to the scope and horse, the scope is not passed through the horse’s mouth.

Although gastroscopy isn’t painful, a tranquilizer is often used to help ensure that the horse remains calm and relaxed throughout.

The procedure usually takes around 15-20 minutes.

To enable a clear view of the stomach lining, it is strongly advised that horses do not eat for at least 12 hours prior to the procedure.

Water can be given immediately after the gastroscopy, if your vet recommends it, and feeding may recommence within a couple of hours, when the horse is fully alert.

Risk Factors Include:

Intensive Exercise

During strenuous training, blood flow to the stomach decreases, and increased pressure in the abdomen pushes acid up into the squamous (non-glandular) section of the stomach. Continued exposure of this sensitive squamous section to acid raises the chance of acid erosion and thus ulceration.


Horses have evolved to eat constantly, producing stomach acid 24 hours a day. If fed infrequently, this stomach acid continues to build up without ingested feed to absorb it, thus increasing the acidity of the stomach.

TIP: Allowing free-choice access to grass or hay and feeding more frequently may help to buffer the acid level in the stomach. Cutting down on the use of high carbohydrate diets may also be helpful.

TIP: Allowing free access to fresh water is a simple step towards reducing the risk of ulcers.


Gastric ulcers can occur in response to physiological stress. For example, shock, respiratory disease and traumatic injury may play a role.

TIP: Ask your vet about any medications or procedures your horse may receive, and be aware of the symptoms of EGUS to look out for.

Stress and Travelling

Transporting horses is linked to the development of gastric ulcers, as psychological distress affects stomach acidity.

TIP: Allowing access to or visibility of other horses may reduce stress in the stable or during transportation. Installing a travel mirror in your horse box or trailer may also be helpful.

TIP: Ask your vet about preventative measures you can take before and during anticipated times of extra strain and stress.