Treating ulcers in horses depends on where in the stomach the ulcers are located. The horse’s stomach has two distinct regions, and each responds to different treatments. Squamous ulcers (in the upper, non-glandular portion) heal reliably with acid-suppressing medication over four weeks. Glandular ulcers (in the lower portion) are more stubborn and often require a different approach entirely. Getting the right diagnosis first is essential, because treating the wrong type can waste time and money.
Recognizing Ulcers Before You Treat Them
Most horses with gastric ulcers don’t show dramatic symptoms. According to UC Davis, the majority can appear completely healthy. The subtle signs are easy to dismiss: poor appetite, dullness, attitude changes, decreased performance, reluctance to train, poor body condition, a dull coat, weight loss, low-grade colic, and girthiness (flinching or pinning ears when the girth is tightened). Some horses walk away from food shortly after starting to eat, as if the arrival of food in the stomach causes discomfort.
More serious cases produce visible abdominal pain or teeth grinding. Foals have their own pattern: intermittent colic after nursing, frequent lying down, diarrhea, a pot-bellied appearance, teeth grinding, and excess salivation. Some foals are found lying on their backs, a position that seems to relieve pressure from severe ulceration.
The only definitive diagnosis is gastroscopy, where a vet passes a camera into the stomach. Ulcers are graded on a 0-to-4 scale in each stomach region. Grade 0 means the lining is intact and healthy. Grade 4 means deep ulceration. This grading matters because it determines how aggressively treatment needs to proceed and gives you a baseline to measure healing against.
Treating Squamous Ulcers
Squamous ulcers are the most common type and the most straightforward to treat. The FDA-approved treatment is omeprazole paste (sold as GastroGard), given orally once daily at 4 mg/kg body weight for four weeks. Omeprazole works by shutting down the acid-producing pumps in the stomach lining, giving damaged tissue time to heal.
After the initial four-week treatment course, prevention of recurrence calls for an additional four weeks at half the dose (2 mg/kg daily). This step-down period is important. Stopping omeprazole abruptly can cause a rebound spike in acid production that damages newly healed tissue. Many owners skip this phase and wonder why ulcers return within weeks.
Most squamous ulcers heal well within the standard 28-day treatment window, though severe grade 3 or 4 ulcers sometimes need a longer course. A follow-up gastroscopy after treatment confirms whether healing is complete.
Glandular Ulcers Need a Different Approach
Glandular ulcers sit in the lower portion of the stomach, where the lining naturally produces acid and mucus. These ulcers don’t respond nearly as well to omeprazole alone. Research suggests that acid suppression isn’t the whole answer here. The problem appears to involve a breakdown in the stomach’s natural defenses: reduced blood flow to the lining, weakened mucus barriers, or an inflammatory process that acid reduction alone can’t fix.
A study of 63 sport horses with glandular disease compared two treatments given over 28 to 35 days. Horses treated with misoprostol (a medication that reduces acid while also increasing blood flow to the stomach lining and reducing inflammation) showed a 72% healing rate. Horses treated with a combination of omeprazole and sucralfate showed only a 20% healing rate. That’s a striking difference, and it’s why many vets now reach for misoprostol as the first-line treatment for confirmed glandular ulcers.
Misoprostol is a prescription medication that requires veterinary oversight. It’s not available over the counter, and the dosing protocol matters. If your horse has been treated for ulcers with omeprazole and hasn’t improved, glandular disease is a likely culprit worth investigating with gastroscopy.
Feeding Changes That Support Healing
Medication treats existing ulcers, but feeding management prevents new ones from forming. The horse’s stomach produces acid continuously, even when empty. Forage acts as a physical buffer, forming a fibrous mat on top of stomach contents that helps prevent acid from splashing onto the vulnerable upper (squamous) region.
The single most important feeding rule: don’t let your horse go more than five hours without forage during the day. Restricted forage should be split into at least two daily meals, but more frequent, smaller meals are better. Give the last meal as late in the evening as possible to shorten the overnight gap.
Why Alfalfa Helps
Alfalfa hay is particularly useful for ulcer-prone horses because of its chemical composition. It contains roughly 178 grams of crude protein per kilogram of dry matter and 15 grams of calcium per kilogram, both significantly higher than grass hay (about 110 g protein and 4.6 g calcium per kilogram). Protein and calcium act as natural acid buffers, meaning they resist pH changes when stomach acid is present. Feeding a flake of alfalfa before exercise or as part of the regular diet helps neutralize stomach acid more effectively than grass hay alone.
Beet pulp is another useful feed ingredient. It contains pectin and lecithin, which form a protective gel barrier in the acidic stomach environment. Lecithin also binds bile acids in gastric fluid and helps stabilize the protective mucus layer on the stomach wall. Adding beet pulp to the diet gives you a second line of nutritional defense alongside alfalfa.
Management Practices That Reduce Risk
Feeding a small amount of forage or alfalfa 20 to 30 minutes before exercise helps create a physical buffer in the stomach. During movement, especially at the trot and canter, stomach contents compress and acid splashes upward onto the unprotected squamous lining. A fibrous mat sitting on top of stomach acid reduces this “acid splash” effect.
Stress is a well-documented trigger. Horses in heavy training, those that travel frequently, and those with limited turnout are at higher risk. Maximizing pasture time gives horses continuous access to grazing, which naturally maintains the forage buffer. Stall confinement with only two meals a day is one of the highest-risk management scenarios for ulcer development.
Watch NSAID Use
Non-steroidal anti-inflammatory drugs like phenylbutazone (“bute”) are commonly used for pain and inflammation, but they carry real gastric risk. These drugs work by blocking enzymes involved in inflammation, but those same enzymes also help maintain the protective lining of the stomach and gut. The damage depends on the specific drug’s selectivity, the dose, and how long it’s used. NSAIDs also delay healing of existing GI damage, so using them in a horse already dealing with ulcers can undermine treatment. If your horse needs ongoing pain management during ulcer treatment, discuss alternatives with your vet.
Preventing Recurrence
Ulcers in horses have a high recurrence rate if the underlying management factors don’t change. A successful treatment course with omeprazole or misoprostol addresses the current damage, but the conditions that caused ulcers in the first place, whether that’s meal spacing, stress, intense training, or limited turnover, will produce new ulcers if left unchanged.
After completing the full treatment and step-down period, the long-term plan should include continuous or near-continuous forage access, alfalfa as a regular part of the diet, pre-exercise feeding, and minimizing unnecessary NSAID use. Some owners keep omeprazole on hand at the prevention dose for high-risk periods like competitions, travel, or changes in routine. A recheck gastroscopy three to six months after treatment can catch early recurrence before it progresses.