Aloe vera (Aloe barbadensis) is a medicinal plant that is frequently used to soothe skin irritations. The gel of the inner leaf is also commonly fed to reduce or prevent gastric irritations and ulcers in horses.
Aloe vera gel contains several active ingredients with anti-inflammatory, anti-oxidant and anti-microbial effects. This herbal remedy also stimulates mucous production and influences gastric acid production.
Although commonly fed to horses as an anti-ulcer agent, there has only been one study to examine the effects of aloe vera effects on horses with gastric ulcers. High doses of aloe powder were shown to improve gastric ulcer severity but not to the same extent as the FDA-approved drug GastroGuard (omeprazole).
Omeprazole remains the standard pharmaceutical treatment for horses with ulcers, but there is growing interest in using natural and herbal alternatives instead.
If your horse has gastric ulcers or is at a high risk of developing ulcers, aloe vera may help but it is also important to address the underlying risk factors that contributed to ulcers forming in the first place.
After dietary and management factors have been addressed, supplements can be used to support gut health and promote intestinal barrier function. Take our quiz to assess your horse’s risk of gastric ulcers and identify ways to reduce risk.
Aloe Vera Uses
Aloe vera is a succulent plant that grows in tropical climates. The gel produced by this plant has long been used in traditional medicine as a topical ointment for skin burns, rashes and other skin conditions.
The leaves of this plant contain a number of active phytochemicals with medicinal benefits, including vitamins, minerals, enzymes, acetylated mannans, polymannans, anthrones, anthraquinone and lectins.
This herb is also used as an oral supplement to support gut health and alleviate gastrointestinal discomfort. Aloe vera juice was historically used for its laxative effects and as a general digestive tonic.
Aloe vera is often used by horse owners to address gastric ulcers. This herb is thought to soothe the digestive tract, reduce pain associated with ulcers and promote wound healing.
Gastric Ulcers in Horses
Ulcers are unfortunately very common in horses – especially in performance horses. It is estimated that up to 90% of horses have gastric ulcers. 
Gastric ulcers are painful lesions in the stomach lining that can contribute to aggression, girthiness, and poor performance. Ulcers can also lead to other problems including poor nutrient absorption, weight loss and poor coat quality.
Horses evolved to spend the majority of their time grazing for food and consuming high-fibre forages. Therefore, they evolved to constantly produce gastric acid.
However, in modern management practices, horses are more prone to ulcers due to intermittent feeding and/or limited access to forage. This creates periods of time when the stomach is empty and unbuffered acid comes into direct contact with the intestinal wall.
Exercising your horse on an empty stomach can also cause so-called splash ulcers as gastric acid splashes into the upper part of the stomach.
Horses most commonly develop ulcers in the squamous non-glandular region of the stomach. This is the upper region that does not naturally have a protective barrier between the stomach lining and the stomach acid.
Ulcers can also develop in the lower, glandular region of the stomach. However, ulcers are less common here as this area naturally produces mucins to form a protective barrier and bicarbonate to buffer the stomach acid.
Aloe Vera for Horses
There are several studies looking at the effects of aloe vera on gastric ulcers in humans, but only one study has investigated the effects of this plant on ulcer recovery in horses.
Horses were enrolled in this study based on clinical signs of ulcers or a previous diagnosis of ulcers. The horses were given either aloe vera gel or omeprazole (4 mg/kg) for approximately 28 days. 
The amount of aloe vera gel administered was based on studies in rats that used high doses and showed beneficial effects on gastric health.  For the horses, this equated to 35 mg of dehydrated inner leaf powder per kg of body weight per day.
For a 500 kg (1100 lb) horse, this is equivalent to 17.6 grams of inner leaf powder per day which is much higher than manufacturer recommendations of 5 grams per day. 
For the horses given aloe vera, there was a 56% rate of improvement in squamous ulcers compared to 85% for the omeprazole group. The rate of healing was 17% for the aloe vera group and 75% for the omeprazole group. 
Although aloe vera did not perform as well as omeprazole for squamous ulcers, the 56% improvement rate is better than that reported in placebo treatments.
There was no difference in the improvement or healing of glandular ulcers between the groups.
It is important to note that this study used a high dose of inner leaf powder. Improvements and healing rates are expected to be lower with typical dosages.
Possible Mechansisms of Action
The inner leaf gel of aloe vera has been used extensively to treat skin issues including burns and wounds.
- Vitamins (A, C, E, B12)
- Minerals (zinc, copper, selenium, calcium)
- Enzymes including starch-digesting amylase
- Fatty acids
- Salicylic acid (a natural form of the active ingredient found in aspirin)
- Phenolic compounds
There are several components of aloe that are beneficial to digestive health. The most-researched components are the soluble polysaccharides, which are large gel-like compounds made of linked sugar molecules.
Acemannan is one polysaccharide in aloe vera that has been shown to support wound healing in various models. It appears to stimulate cells of the immune system to accelerate healing processes and bind to macrophages to activate the removal of pathogens from the area and protect from infection. 
In addition, direct contact of non-starch polysaccharides such as acemannan with cells lining the digestive tract can enhance calcium absorption into the cells. Calcium ions are important for activating stem cells, which are needed to replace the damaged tissue.
In some models, acemannan also induces the expression of vascular endothelial growth factor (VEGF) which is important for maintaining blood vessels that bring nutrients to the area and remove waste products. 
VEGF also increases prostaglandin E2 production which promotes gastric ulcer healing in animal models.  Low levels of prostaglandin E2 have been implicated in the formation of gastric ulcers in horses, particularly in the glandular region. 
Additional Benefits of Aloe Vera
Although the main reason to feed aloe vera to horses is to support gastric health, there may be other benefits as well.
Research studies in animal models, humans and cell culture have shown several effects including: 
- Antioxidant activity: Anthraquinones are phenolic compounds that bind free radicals to prevent them from causing damage to tissues.
- Antimicrobial activity: Aloe-emodin is an anthraquinone that inhibits proliferation of pathogenic microbes such as those of the genus Clostridium or Streptococcus
- Prebiotic activity: The polysaccharide acemannan can feed beneficial microorganisms to increase production of short-chain fatty acids that can be used as an energy source by the animal and alter microbial composition
- Antidiabetic: Polysaccharides in aloe vera have been shown to decrease blood sugar levels in animal models and improve the health of insulin-producing cells in the pancreas
- Anticancer: In cell culture and animal models, aloe extracts reduce cell proliferation and induce cell death, which helps shrink tumors
These benefits have mostly been demonstrated in animal models and cell lines using high doses of gel extract. More research is required in horses to verify these effects.
Feeding Aloe Vera to Horses
The benefits of aloe vera appear to be more prominent when given at high doses. This supplement can be given as powder, gel or juice.
Typically recommended feeding rates for aloe vera supplements in horses are as follows. 
- Aloe vera powder: 5 grams dissolved in 250 ml of water per day
- Aloe vera gel: 20 ml by syringe twice per day
- Aloe vera juice: 5 ml per hand of height or 10 ml per hand of height when ulcers are present. This is equivalent to 80 – 160 ml for a 16 hh horse
Note that in the research study conducted by Bush et al , a dosage of 17.6 grams for a 500 kg horse was used for gastric ulcers.
This dosage is much higher than what is typically recommended by manufacturers of equine aloe products. More research is needed to evaluate efficacy at commonly used feeding rates.
Supporting Gastric Health in Horses
If you suspect your horse has gastric ulcers there are several dietary and management adjustments to consider that will help reduce your horse’s risk of ulcer recurrence in the future.
Some common signs that your horse may have ulcers include:
- Aggressive or nervous behaivour
- Stereotypic behaviours such as cribbing
- Poor appetite
- Sensitivity in the girth area
- Reluctance to exercise
- Poor performance
The only definitive way to diagnose gastric ulcers is via gastroscopy performed by a veterinarian. However, this is not always accessible and may be cost-prohibitive.
Because rates of ulceration are so high among exercising horses, many horse owners will presume a diagnosis upon observing one or more of the common signs of gastric ulcers.
Addressing Causes of Gastric Ulcers
Causes of gastric ulcers may be related to diet composition, feeding patterns, exercise or stress levels. There are several key practices that can help to reduce your horse’s ulcer risk.
Maximize forage intake and availability
A common contributing factor to ulcers is horses with low forage intake or long periods without access to forage, resulting in more time with an empty stomach.
If the stomach is empty, gastric pH in the squamous region will be lower and the horse will have an increased likelihood of gastric ulcers forming.
Provide free-choice forage whenever possible to minimize the time that the stomach is empty.
Limit high grain feeds
High grain meals pass through the stomach quickly, leaving it empty for long periods. Grain meals also produce less saliva during chewing than hay. This means there is less saliva entering the stomach to buffer gastric acid.
If your horse requires more energy than what forage provides, consider feeding oil or highly digestible fibre sources such as beet pulp or soy hulls.
These feeds will meet your horse’s energy needs while supporting gut health and limiting starch intake.
Avoid excessive exercise
High-intensity exercise is a common risk factor for gastric ulcers. In one study, 91% of Thoroughbreds in race training had gastric ulcers and 100% of actively racing horses had ulcers. 
Exercise increases abdominal pressure, which pushes the highly acidic contents of the stomach from the glandular region into the squamous region. Splash ulcers can form as the unprotected squamous area is exposed to stomach acid.
Exercise also reduces blood flow to the stomach, which can inhibit healing and negatively affect the integrity of the tissue if exercise is prolonged.
Horses in competition may also experience long periods without access to feed or water during travel. The stress of travel and trailering also increases ulcer risk.
To lower the risk of ulcers from exercise, feed your horse hay or forage cubes prior to exercise and acclimate them to stressors such as trailering.
When your horse experiences stress, the adrenal glands release more of the stress hormone cortisol, which lowers prostaglandin production. Prostaglandins help maintain a healthy stomach lining.
Common stressors to avoid include:
- Changes to herd dynamics
- Stall confinement
- Social isolation
- Limited forage access
- Blocking natural behaviours
Minimize the use of NSAIDs
Non-steroidal anti-inflammatory drugs (NSAIDs) such as phenylbutazone are commonly used to treat pain. However, these drugs can also block prostaglandin production in the stomach and increase the risk of ulcers.
If your horse requires NSAID treatment, ask your veterinarian about using COX-2-specific forms of analgesics, which are less likely to induce gastric lesions.  Work closely with your vet to establish an appropriate dosing protocol to minimize the risk of gastrointestinal side effects.
Supplements for Gastric Ulcers
Consult with your veterinarian and equine nutritionists to address possible diet and management factors that may be contributing to ulcer risk. Also consider adding a gut health supplement that targets gastric health.
Aloe vera is one option that may be beneficial for your horse, but its efficacy is only moderately better than a placebo. It may work better in combination with other ingredients that have been shown to improve gastric ulcers.
Mad Barn’s Visceral+ has been clinically tested to reduce ulcers in horses following the discontinuation of omeprazole treatment. Visceral+ is made with safe and natural ingredients that are research-validated in horses with ulcers.
Visceral+ is formulated to support the body’s healing processes while providing ingredients to nourish the microbiome and decrease pathogen load. Unlike antacids or proton-pump inhibitors, Visceral+ does not alter gastric acid production and instead works with the horse’s natural biology. 
If you’re interested in feeding aloe vera or any other gut health supplement to your horse, we recommend also looking at your horse’s overall diet and management to identify ways to support gut health.
You can submit your horse’s diet for evaluation by our equine nutritionists to learn strategies to reduce ulcer risk while providing a balanced diet.
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