Gastric ulcers (EGUS) in horses

What is EGUS?

EGUS (Equine Gastric Ulcer Syndrome) is an umbrella term for two separate conditions, each with its own cause, treatment and prognosis [1]:

• ESGD (Equine Squamous Gastric Disease) — damage to the squamous epithelial tissue in the non-glandular part of the stomach, caused by exposure to gastric acid
• EGGD (Equine Glandular Gastric Disease) — damage to the glandular mucosa in the lower stomach segment, with a different underlying cause

Prevalence is high: in racehorses in intensive training, up to 100% of animals may be affected; in leisure horses, this ranges from 11 to 79% depending on the population [2].

Diagnosis: gastroscopy is essential

Blood values, faecal examination and clinical signs alone are insufficient to confirm or rule out EGUS. Gastroscopy — endoscopic examination of the stomach — is the only reliable diagnostic method [1]. This distinction is crucial: ESGD and EGGD require a different approach, and treating without a diagnosis significantly increases the risk of treatment failure.

Proven treatment

ESGD

Omeprazole (proton pump inhibitor, first choice under trade names such as GastroGard) is the indicated treatment. With correctly dosed oral administration, healing occurs in 67–100% of cases [1][2].

EGGD

In glandular stomach disease, omeprazole as monotherapy is inadequate: only 14–25% healing. The recommended approach combines omeprazole with sucralfate for a minimum of 8 weeks [1][2].

After the treatment course, reassessment via gastroscopy is recommended before medication is stopped. Abrupt cessation can trigger rebound hyperacidity.

Supplementary and natural options

Many owners resort to agents such as aloe vera, slippery elm, calcium carbonate buffers or herbal mixtures. For none of these agents is there currently sufficient scientific evidence that they heal gastric damage in the horse or can replace a proven treatment [2]. They are not an alternative to gastroscopic diagnosis or medicinal products.

Feed management occupies a different position: continuous access to roughage physically buffers gastric acid and lowers the risk of ESGD. This is not a treatment, but a preventive measure with solid mechanistic substantiation. If the horse already has damage, feed management is adjunctive to — not a replacement for — medical treatment.

Supplementary options are only useful as support alongside an established treatment plan following gastroscopic diagnosis.

Risk factors and prevention

Known risk factors include intensive work, limited or irregular roughage, NSAID use, transport and stressful conditions [1][2]. Preventive omeprazole courses demonstrably reduce the risk in racehorses in intensive training, as shown by meta-analysis [3]. Risk reduction through management — more roughage, less stress, cautious NSAID use — is relevant for every horse, regardless of discipline.

Sources

[1] Sykes et al. — ECEIM Consensus Statement on EGUS in Adult Horses — Journal of Veterinary Internal Medicine (2015). Read article

[2] Vokes et al. — Equine Gastric Ulcer Syndrome: An Update on Current Knowledge — Animals (Basel) (2023). Read article

[3] Varley et al. — Prophylactic omeprazole for prevention of EGUS: A meta-analysis — Equine Veterinary Journal (2019). Read article