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 Plant Properties

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.

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Aloe Vera Mechanisms of Action

The inner leaf gel of aloe vera has been used extensively to treat skin issues including burns and wounds.

It contains at least 75 different compounds that could explain its purported antioxidant, anti-inflammatory, wound-healing and pain-relieving benefits. These include: [3][8]

  • Vitamins (A, C, E, B12)
  • Minerals (zinc, copper, selenium, calcium)
  • Enzymes including starch-digesting amylase
  • Sugars
  • 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. [4]

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. [5]

VEGF also increases prostaglandin E2 production which promotes gastric ulcer healing in animal models. [6] Low levels of prostaglandin E2 have been implicated in the formation of gastric ulcers in horses, particularly in the glandular region. [7]

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: [3]

  • 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.

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. [11]

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. [12]

Horses evolved to spend the majority of their time grazing for food and consuming high-fibre forages. Therefore, they evolved to constantly produce mucous which acts as a buffer in the stomach.

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. [1]

The amount of aloe vera gel administered was based on studies in rats that used high doses and showed beneficial effects on gastric health. [13][14] For 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. [2]

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. [1]

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