A way to improve or resolve a condition or diagnosis. This might include resolving the underlying cause or treating the signs of disease (symptomatic treatment).

Cost: $500 to $1,000

These cost ranges are approximate and may vary from region to region.
Additional charges may also apply.

YOUR VET MAY Recommend

Omeprazole (Gastrogard®, Ulcergard®)

Cost: $500 to $1,000

These cost ranges are approximate and may vary from region to region.
Additional charges may also apply.


The most effective treatment for gastric ulcers in horses is the prescription drug omeprazole, brand names Gastrogard® and Ulcergard®.

Omeprazole binds to acid producing cells in the stomach, and irreversibly stops acid production. Since more of these cells are constantly formed, there is a need for ongoing treatment. This drug actually passes through the stomach, is absorbed into the bloodstream in the small intestine, and then affects the acid producing cells.

Gastrogard® and Ulcergard® are exactly the same medication, omeprazole.

Gastrogard® is labeled and dosed for the treatment of ulcers. Ulcergard® is labeled for the prevention of ulcers and is given at a lower (preventative) dose. Both are specially formulated pastes developed from a drug used to treat ulcers in humans. They are highly effective but also very expensive, long term.

Vets cannot legally prescribe compounded omeprazole at this time since the brand name formulations are FDA approved. There is also some thought that compounded omeprazole is not as effective as the brand name products.

Omeprazole is only intended to treat stomach ulcers. It has no value in treating colonic ulcers, which also occur in horses.


Your vet does their best to make a diagnosis before using this drug. They explain the advantages and disadvantages of this expensive treatment, and any other treatment options. They provide options for monitoring treatment effectiveness.


Be as objective as possible with respect to assessing your horse's behavior while both on and off of this drug. The differences may be subtle. Keep track of signs and report this to your vet. Give the medication as directed. Follow up and schedule diagnostics recommended by your vet to determine the effectiveness of this treatment.

my vet's role


Omeprazole is considered safe in horses. However, reduced acid production reduces the barrier to intestinal infection with bacteria, thus making enteritis or colitis more likely. This side effect is not well understood in horses, but is a theoretical concern in adult horses. It has actually been found to be the case in foals, so in foals it's best to use this medication when we know we have an ulcer problem, and not as a prophylactic.

Reduced acid production may also affect digestion and nutrient absorption.

Once discontinued, there can be a rebound effect of increased stomach acidity that can encourage the recurrence of ulcers.


Omeprazole is a prohibited substance in some equine competitions. Check your sport's regulations to be sure that use of this medication is legal during competition.

your role

Is it working? Timeframe for effect.
Omeprazole takes several days to fully decrease stomach acid (increase the pH). Therefore vets don't expect to see improvement in pain and other signs of gastric ulcers until day 3.

The healing course for ulcers is 2-4 weeks of treatment. Four weeks is usually recommended. After 2 weeks, another gastroscopy exam can be performed to assess healing.

However, an improvement in the horse's behavior does not necessarily mean the ulcers are healed.
Questions To Ask Your Vet:
  • How long do I need to treat with the full dose of Gastrogard?
  • How will we know whether this medication makes a difference?
  • What do I need to do to prevent recurrence of gastric ulcers once the medication is discontinued?
  • Are there any less expensive, alternative medications to treat my horse?

Related References:

Furr M, Cohen ND, Axon JE, et al. Treatment with histamine-type 2 receptor antagonists and omeprazole increase the risk of diarrhoea in neonatal foals treated in intensive care units. Equine Vet J, Perinatal Suppl 2012;41:80-86.

Author: Doug Thal DVM Dipl. ABVP