Skip to Content

Horse Ulcers 101: How to Recognize, Treat, and Prevent Them

Published on: December 20, 2022

By: Miles HenryFact Checked

Any links on this page that lead to products on Amazon are affiliate links and I earn a commission if you make a purchase. Thanks in advance – I really appreciate it!


My filly is feisty, always lashing out at anyone who dares to get close. But lately, her aggression has increased, and I can’t figure out why. A friend mentioned the possibility of ulcers. So, I did some research and contacted my veterinarian to have him check her for ulcers.

Horse ulcers, or equine gastric ulcer syndrome, occur when the protective lining of the stomach or small intestine becomes damaged, leading to the development of painful sores. While ulcers can affect any horse, they are more common in performance horses and those that experience stress or changes in diet and routine.

While ulcers can be a serious issue for horses, they are also highly treatable with the proper diagnosis and management. In this post, we will delve into the signs, causes, and treatment of ulcers in horses, so you can better understand and manage this condition in your horses.

What Are Equine Ulcers?

Equine gastric ulcer syndrome (EGUS) is sores that form in the horse’s esophagus, stomach, and small intestines. Ulcers are graded into four categories, ranging from mild to acute sores. Acute sores can become perforated, leading to internal leakage that can be extremely dangerous, if not fatal.

Picture of a colt I suspect has ulcers.
A colt with ulcers.

Ulcers in horses are a common yet often overlooked condition that can affect any horse at any age. However, they are more commonly seen in athletic horses that are subjected to high levels of physical activity, such as racing, showing, and endurance sports.

In fact, research has shown that ulcers can affect as many as two out of three horses, making it important for all horse owners to be aware of the signs, causes, and treatment of this condition.

Ulcers can cause a range of symptoms in horses, including discomfort, weight loss, poor coat condition, and changes in behavior and appetite. If left untreated, ulcers can lead to more serious health problems, such as colic and malnutrition.

Therefore, it is crucial to be vigilant for signs of ulcers in your horse and to seek veterinary care if you suspect your horse may be suffering from this condition.

The horse pictured above began to get lethargic and lose weight, and his coat changed dramatically and began to look poor. He is showing some signs of ulcers.

What Types Of Ulcers Do Horses Get?

Horses have complex stomachs, meaning they have two types of lining in their gut. The top part of the stomach is the squamous epithelium; this section does not produce any acid and does not have any protective factors.

The lower part of the horse’s stomach where the acid is produced is called the glandular epithelium, where horses can produce up to sixteen gallons of acid. The production of acid is continuous and not triggered by feeding.

Another form of ulcer that horses can suffer from is hindgut ulcers or right dorsal colitis (RDC). This is a specific ulceration found in the upper right section of the horse’s colon. This ulcer is caused by inflammatory bowel disorder due to the administration of phenylbutazone, a non-steroidal anti-inflammatory.

Hindgut ulcers are more difficult to detect, but it’s not impossible to get a positive diagnosis.

So, the three different ulcers horse can suffer from are

  • Squamous mucosal ulceration
  • Glandular mucosal ulceration
  • Right dorsal colitis (hindgut ulcerations)

Here is a helpful YouTube video on Equine Gastric Ulcer Syndrome.

What Are The Signs That A Horse Has Ulcers?

As my friend mentioned, irritability can be a sign of horse ulcers. However, many clinical signs of ulcers can be challenging to diagnose as these conditions in mild conditions are asymptomatic.

However, there are some signs to look for that could provide clues as to chronic diseases of ulcers.

  • Mild sporadic colic
  • Diarrhea
  • Weight loss
  • A decline in body condition
  • Rough hair coat
  • Irritability and change in attitude and mood
  • Lack of energy and stamina
  • Reluctance under saddle
  • Loss of appetite
  • Girthiness
  • Stiffness
  • Sore back
  • Nervous, aggressive, and self-mutilation
  • Change in eating pattern
  • Teeth grinding

How can a vet be sure your horse has ulcers?

A veterinarian can positively confirm an equine ulcer by performing a gastroscopy. This diagnostic test involves inserting a flexible endoscope (a long, thin tube with a camera on the end) through the horse’s mouth and into the stomach to visualize the lining of the stomach and small intestine. This allows the veterinarian to directly examine the digestive tract and identify any ulcers present.

Picture of my mean filly I suspect has ulcers.
Mean filly

What Are The Causes Of Ulcers In Horses?

Ulcers in horses are a common digestive disorder. But what causes ulcers to develop in horses in the first place? The answer is complex, as there are several factors that can contribute to the development of ulcers in horses.

Infograph of horse ulcers in a summary form.

Horses are slow grazers that feed continuously. Therefore, their stomachs produce constant acidic fluids, up to sixteen gallons per day, to break down the roughage and food that horses eat.

The production of saliva is produced when horses eat. More saliva is created when they eat hay compared to grains and concentrates. Food and saliva help to buffer the acid in the stomach, while the grass helps to line the stomach and keeps the acid fluids in the lower half of the stomach.

When horses are prevented from eating before riding, the acidic fluids in the stomach tend to splash around. These juices come into contact with the upper part of the stomach (squamous mucosal), which has no protective factors, causing ulcers.

Several risk factors can cause horses to develop ulcers.

Risk Factor #1: Feeding And Feeding Patterns

Horses are grazing animals that graze twelve to fourteen hours a day when turned out. So, feed composition is essential as hay should constitute most horses’ feed.

  • Periodic feeding
  • Periods greater than six hours between foraging increase the risk of EGUS
  • Removing food before riding
  • Change in feeding routines
  • Reduced access to water

Hay increases the stomach pH (becoming more alkaline), reducing the risk of high acidic levels and ulcerations.

Concentrate feeds increase pepsin, hydrochloric acids, and volatile fatty acids that lower the pH of the stomach contents creating an acidic environment.

Risk Factor #2: Stress-Related Situations

Like humans, horses are prone to suffer from stress-related situations that can increase the risk of gastric ulcerations.

Exercise is an integral part of a horse’s life. Competitive horses are athletes and need to be kept in top shape, so their schedules are filled daily with some form of exercise.

  • Injury
  • Pain
  • Lameness
  • Surgery
  • Training
  • Prolonged use of medications such as corticosteroids or non-steroidal anti-inflammatory

Risk Factor #3: Behavioural Stress

Some of these may seem trivial to us. Still, some of these behavioral stresses can cause a massive rift in a horse’s life, creating stress that elevates the production of acidity in the stomach and creates an environment for ulcers.

  • Stall confinement
  • Transportation
  • Being in unfamiliar environments, such as shows or moving to a different area
  • Social regrouping of horses and the redefining of group hierarchy
  • Weaning of foals
Picture of a two year old filly.

How Can You Prevent Your Horse From Getting Ulcers?

In some cases, you can help prevent ulcers in horses by better managing the horse’s daily activities. Digestive support is also essential as a way to prevent ulcers.

When feeding, ensure that at least fifty percent, preferably seventy percent, of the horse’s feed is made up of hay or pasture. Reducing the amount of grain fed or increasing the number of meals is also essential to help manage and prevent ulcers.

Hay is a buffer against the acid in the stomach. In addition, the constant grazing and chewing stimulate saliva, which also acts as a buffer against the acid, so providing a continuous supply of hay is helpful. If you want to prolong the eating time, feed hay in hay nets or double hay nets to reduce the size of the holes. This will slow down the horses eating, prolonging the hay.

Here are a few preventative measures to reduce the risk of your horse getting ulcers.

  • Increase turn out time into pastures.
  • Break down high levels of concentrations into smaller quantities more frequently.
  • Ensure the majority of the horse’s overall daily feed consists of hay
  • Offer a free choice of hay when stabled or the possibility of pasture
  • Reduce the amount of grain concentrates
  • Feed alfalfa hay; this is a natural antacid for horses
  • Feed hay in hay nets to slow the eating process.
  • Add chaff to meals to encourage more chewing, increasing salivation.
  • Feed hay in hay nets
  • Reduce or minimize the use of anti-inflammatory drugs if possible.
  • Ensure the horse has plenty of water at all times
  • Regulate the starch and sugar intake of the horse
  • Using Ultraguard as a preventative measure by dosing the horse daily or starting two days before any stressful event can help control the acid in the horse’s stomach.
  • Feed your horse hay before exercising.
Picture of a 44 lb. bale of hay.

What Should You Feed A Horse With Stomach Ulcers?

A horse’s diet with stomach ulcers should be carefully managed to help reduce irritation to the ulcerated areas and promote healing. Here are some general guidelines for feeding a horse with stomach ulcers:

  1. Provide a diet high in forage: A diet that is high in forage (alfalfa, good-quality grass hay, or pasture) can help reduce the risk of ulcers and promote healing. Forage should make up at least 50% of the horse’s diet.
  2. Avoid high-grain diets: High-grain diets can increase the risk of ulcers, so it’s important to minimize the amount of grain in the diet of a horse with ulcers.
  3. Offer small, frequent meals: Feeding smaller, more frequent meals can help reduce the amount of stomach acid present and allow the ulcerated areas to heal.
  4. Consider adding a digestive aid: A digestive aid, such as a probiotic or prebiotic, can help support healthy digestion and reduce the risk of ulcers. Adding oil supplements such as corn or rapeseed oil can also reduce gastric acid production.

It’s important to note that every horse is different, and the specific dietary needs of a horse with ulcers will depend on the severity of the ulcers and any underlying medical conditions. It is always best to consult with a veterinarian for an accurate diagnosis and an appropriate treatment plan.

Note: Alfalfa hay is high in protein and low in starch and sugar, which helps reduce acid production in the stomach and acts as an antacid for horses.

What Is The Best Treatment For Horses With Ulcers?

Raising and maintaining the pH level above 4.0 for at least the majority of the day is essential when treating horses with ulcers.

The best treatment for horses with ulcers is by improving their dietary conditions, reducing grains, or splitting grain meals into three or four smaller meals accompanied by plenty of foraging or good quality hay.

Reducing sugar and starch is also vital in controlling the acid produced. So, replacing sweet barley or oats with alfalfa helps manage and prevent ulcers.

Medical treatments come in four categories. They are effective but should not be considered a cure. Once the medication stops and the stressors and dietary conditions of the horse have not been addressed, the reoccurrence of ulcers is inevitable.

There are four categories of medical treatments.

  • Antacids (Sodium bicarbonate)
  • Histamine H2 Blockers (Cimetidine, ranitidine, and famotidine)
  • Protective coating medicine (Sucralfate and Lecithin)
  • Proton pump inhibitors (Omeprazole and pantoprazole)

It’s also important to remember that prevention is always better than treatment. If you suspect that your horse may be at risk for ulcers or is showing any of the symptoms of ulcers, it’s important to consult with a veterinarian for an accurate diagnosis and an appropriate treatment plan.

What Is A Natural Remedy For Horse Ulcers?

Natural remedies that can assist in the treatment of ulcers use herbs  and plants such as;

  • Garlic powder
  • Aloe vera juice
  • Licorice powder
  • Slippery elm
  • Fenugreek
  • Lemon balm
  • Mint
  • Chamomile
Picture of an old mare that may have ulcers.
Mare showing signs of ulcers.


Our lifestyle is always busy and on the go, leaving little time to consider its impact on our horses. Stressors like intermittent feeding, incorrect feed, exercise, and stall confinement all increase acid levels in our equine friend’s stomach.

So, it’s critical to know the signs to look for and how we can help treat these conditions that significantly affect the mood and performance of our riding partner. Here are some things to keep in mind:

  • There is no breed-specific horse that is more prone to ulcers.
  • Gastric ulcers affect any breed of horse and at any age, from foals to older horses.
  • Racehorses are most affected by this ailment, with two-thirds of competitive horses suffering from ulcers.
  • Diet and rest, coupled with medication and preventative measures, can help a horse heal from these painful sores that are often asymptomatic.


Can horse ulcers go away on their own?

Yes, ulcers that occur in horses can go away on their own. However, it is important to seek veterinary care for a horse with ulcers as they can be a sign of a more serious underlying condition and can cause discomfort or pain for the horse.

How Do You Soothe A Horse With Ulcers?

Slippery elm and mint are said to calm inflammation in the stomach providing soothing relief to the horse’s painful ulcers.