Integrative approach to diarrhea in the equine

Diarrhea is common in horses, and can be stubborn to treat. Alternative therapies offer a safe and effective way to resolve the problem.

The horse’s digestive tract is very complex, sensitive to its environment, and prone to complications. It is also abused with an overabundance of antibiotics, non-steroidal anti-inflammatories, de-wormers and many other drugs. Additionally, horses are often under stress, either for performance or in the way they are housed and handled. One of the common signs of an imbalanced digestive tract is diarrhea. An integrative approach to treatment is the most effective way to manage most cases.

Diarrhea symptoms

A horse’s manure can vary significantly though the year, depending on the main roughage source. Hay-fed horses can have very dry fecal balls, while fresh spring grass-fed horses almost always have loose wet stool. Alfalfa hay-fed horses may have naturally loose manure. If you are unsure about the effects of the feed on a patient, check the other horses on the same roughage regime.

From a holistic perspective, it is important to ask and observe the details of the stool condition — odor, frequency and consistency. Ask about signs of discomfort before, during and after the stool passes. This could be seen as restlessness, moving around quickly as the stool ends, circling the stall before defecating, or making grimacing faces during the passing.

It is helpful to observe the color and moisture of the tongue and gums. TCVM practitioners are trained to incorporate that information, but all practitioners can benefit from this information. As treatment progresses, how does the tongue color and moisture change? Clients can be taught to observe these details and report changes.

Acute diarrhea

Diarrhea diseases in the horse can be life-threatening and are most often treated in hospital settings. The most serious are Salmonella, Clostridium difficile and Potomac Horse Fever. Coronavirus is being recognized as not just an opportunist, but an actual pathogenic cause of diarrhea. Parts of the country with sandy soil also see diarrhea associated with sand ingestion and accumulation. Antibiotics have been shown to be one of the most important causes of serious colitis in horses.1

Chronic diarrhea

The symptoms of chronic diarrhea in horses range from watery fluid passing with formed feces to projectile diarrhea. The majority of cases seen by integrative practitioners are chronic and non-life threatening, with some being very long-standing and unresponsive to conventional treatment.

Ulcers are commonly associated with loose stool in some horses. These are usually hind-gut ulcers, but can occur anywhere in the digestive tract. Testing with the Succeed Fecal Blood Test is a non-invasive, low-stress method to determine if ulcers could be the cause. Endoscopy can also be performed.

One of the most common complaints is stool that is partially formed, but accompanied by a significant amount of acrid, brown watery fluid that can build up in the tail and is difficult to remove in the winter. This is most common in the cooler seasons of the year. Some horses seem to be triggered by eating hay, and are non-symptomatic on grass.

Older horses, especially those in their 20s and above, may have poorly-formed stool or the above symptoms of partially formed combined with watery fluid. These horses may have an aging digestive tract, with a weaker microbiome, or a poorly-functioning enzyme system. Horses fed a wet diet due to a lack of teeth may be getting more water than they can process, with diarrhea as the result.

The horse’s microbiome

The genetic makeup of the microbiota is called the microbiome.2 The microbiota grow on prebiotics, not on the intestinal wall. Populations of microbiota are quite variable between horses, even among those kept on similar feeding programs.3,4 There is a great deal of variation throughout the digestive tract of each horse. Because they reproduce rapidly, microbial populations are susceptible to changes in diet and environment. Research into equine microbial populations using DNA testing is just beginning, as it the understanding of how the balance of microbes relates to health and disease.5,6,7

The normal pH of the intestinal tract changes from acidic in the stomach and upper small intestine, to alkaline in the large intestine. The microbial balance helps keep the pH in the correct range, and and pH keeps the microbes in balance. When microbial populations move to incorrect locations in the gut, the tissue may become inflamed, leading to diarrhea.

An organic garden for your horse

A new idea I have for restoring the natural soil-based microbiome in horses is to plant a corner of the property as a high quality organic garden, using grasses and herbs that horses naturally will eat. Allow ten minutes of grazing per day to provide natural microbe populations that cannot be supplied from a package.

Causes of diarrhea

Many factors can lead to loose stools or diarrhea in horses.

  1. Feeds, feed changes and variations in forage have been shown to change the microbiota significantly.8 Some horses adapt well, while others develop wetter-than-normal manure. Excessive grain affects the microbiota and can lead to changes in stool consistency. Food allergies or intolerances to common feed ingredients, especially alfalfa, can lead to inflammation and diarrhea.
  2. Glyphosate, the herbicide used in genetically modified organism (GMO) feeds has been shown to increase ulceration of the intestinal tracts of pigs.9 Diarrhea was not one of the symptoms in the pigs; however, inflammation of the intestinal tract in the equine can lead to loose stool.
  3. Drugs, especially NSAIDs, can lead to diarrhea in sensitive individuals. Along with antibiotics, these drugs are implicated in inflammatory lesions throughout the digestive tract, and changes in the microbiota.1
  4. Weather changes, especially cold and damp conditions, lead to stool changes. TCVM pays particular attention to weather effects, and clinically this author sees many more cases of diarrhea during such conditions. Large swings in temperature and barometric pressure are also a factor.

General review of TCVM and digestion

A useful way to understand the workings of the gut is to take a Traditional Chinese Veterinary Medicine (TCVM) perspective. The treatment choices do not need to be Chinese.

It is beyond the scope of this article to give a complete lesson in Chinese Medicine, but here is a summary.

  • The Stomach (ST) receives and ripens incoming food and drink. The pure or clear part descends to the Spleen (SP) while the turbid part goes to the small intestine. The energy of the ST needs to move in a downward direction to accomplish this.
  • The SP is responsible for generating and containing the Blood and keeping fluids in the proper place. A SP Qi deficiency can allow too much fluid to escape through the digestive tract, leading to diarrhea.
  • The Kidney (KI) Yang provides Fire for digestion and vaporizes the water in the lungs, allowing it to descend and dispersing the fluids in a downward direction (the natural direction of the lungs). The KI Yang also assists the SP Yang in vaporizing the fluids. If the Yang is deficient, the fluids escape downwards.
  • The Liver (LV) governs the smooth movement of Qi through the vessels and organs and also stores the Blood. The SP has a close relationship with the LV. The LV maintains an upward Qi flow and releases bile to help digestion. When the LV Qi stagnates (a common occurrence in the equine) it over-controls the SP and damages it. This can lead to ulcers, and loose stool. The LV is the Chinese organ most affected by stress, hence the prevalence of ulcers in modern horse-keeping.
  • The Large Intestine (LI) reclaims and excretes downward the more solid parts of the food and drink, and reabsorbs water from the waste material.

Products for diagnosing and treating equine diarrhea

Succeed Fecal Blood Test,

Spore Probiotics,

Minerals for bacterial communication — Restore,

Western herbal formula — Digest Support,

Psyllium-based product — Assure Plus,

Organic enzyme product,

Treating equine diarrhea

Acute, severe cases are best treated in a hospital setting with access to intravenous fluids, along with acupuncture, probiotics, fecal transplants and antibiotics if needed. In some cases, the antibiotics are the cause of severe diarrhea and the treatment needs to be done without them. Replenishing the microbiome is perhaps the most important aspect of treatment, since the microbial population has been compromised.


Acupuncture has been clinically shown to be an effective adjunct to treating acute diarrhea, and is used at several universities with trained clinicians.10

Acupuncture can also be a first-line treatment for many chronic cases, and may be all that is needed. To be effective, an accurate TCVM diagnosis is made and points are selected based on the diagnosis. Several universally useful points include ST 36, BL 20 and 21, SP 6 and 9, LI 10 and GV 1.


The most important GI supplement is a good probiotic formula. Horses in general are treated with antibiotics for every little cut and scrape, not to mention every upper respiratory infection. In many cases, supplementation with a probiotic will be the key to repairing gut function and may be the only extra supplement needed.

Any horse showing signs of ill health would do well with at least two months of probiotic treatment. Useful probiotics usually contain some or all of these beneficial bacteria: Lactobacillus acidophilus, L. plantarum, L. casei, Enterococcus faecium, Bifidobacterium thermophilum and B. longum. A Lactobacillus Acidophilus fermentation product can also be used to stimulate bacteria growth.

Many probiotics are poorly-made and unstable, so by the time they are purchased and used, they may or may not contain active ingredients. Beware of heavily-preserved formulas and those with artificial flavorings and sweeteners.


Prebiotics are usually short-chain fructo-oligosaccharides that support the growth of probiotic bacteria. They can be quite beneficial in a formula.

The microbiome is often best supported with some of the newer products that include soil organisms, the spores of the microbes or the minerals that form the communication network for the bacteria.

Fecal transplantation

Fecal transplantation has been performed for many years in equine practice.11 Most of the research and clinical papers have focused on severe, acute cases, or antibiotic-induced colitis. As microbiota DNA analysis becomes more available, it will be possible to accurately select healthy donor horses, and potentially commercialize a fecal microbiota for easy administration.

Herbal supplementation

Herbs from many traditions can be used to treat diarrhea. Horses are easy to feed with herbs since they are capable of digesting raw plant material. In many cases, horses will selectively choose the herbs they need and reject those they don’t. Some horses are quite picky and will not eat any form of the herb, but they are usually the exception rather than the rule. A horse that eats herbs well, then refuses them, likely does not need that formula anymore.

Dosing is generally two to four times the human dose, whether the herbs are raw or in tincture form. Horses are quite sensitive to the energy of herbs, and in many cases will respond to even lower doses. Herbs can be mixed with palatable feeds or mixed with liquid and syringed into the mouth.

Western herbal mixes can contain herbs such as yarrow, mullein, hops, marshmallow, meadowsweet or cinnamon if a warming herb is needed. Formulations prepared with the knowledge of the energetics of herbs are usually more effective than just symptomatically using them. High cannabinoid-containing hemp has anti-inflammatory action in the gut, and early usage in the equine shows promise as an herbal support to the gut.

Chinese formulas are selected based on the TCVM diagnosis, which can be SP Qi Deficiency, SP Yang Deficiency, or a formula to clear Heat in an infectious cause of diarrhea.

Additional supplements

Simple nutritional supplements can be very effective depending on the clinical presentation. Psyllium and probiotics can help not only with sand accumulation, but also with soothing and healing the gut wall.12 Enzymes can be useful especially for older horses whose overall body functions are failing, or those that have long-standing absorption problems.


Homeopathy can be very useful in the treatment of diarrhea. Simple cases can be treated with remedies such Arsenicum Alb, Sulphur, Veratrum Alb and Lycopodium. There are many choices in the Materia Medica, so it is important to use the details of the condition to pick the remedy. For example, Arsenicum Alb works very well with projectile diarrhea in Potomac Fever, or in horses that are restless and thirstless, while Sulphur works with cases that have extremely offensive-smelling diarrhea, that may or may not be profuse.


Chiropractic is not often thought of as a treatment for diarrhea, but itshould be considered in chronic situations. A horse that is not responding well to other treatment, should be checked to ensure his spine has normal motion throughout, especially in areas from the sixth thoracic vertebra and down, where various spinal nerve roots affect the digestive tract.


Diarrhea in the equine is a common, and at times, challenging condition. Daily assaults on the digestive tract through extensive use of drugs, poor feeding regimes and stress affects the microbiome in a negative manner. Natural approaches to treatment are more cost-effective, successful and healthier for the horse than the typical drug regimen. Many horses need ongoing support, since the conditions surrounding the diarrhea are often unavoidable, and a natural approach offers safe and effective therapies.


1Gustafsson, Agneta. “Antibiotic associated diarrhea in horses”. Acta Universitatis agriculturae Sueciae. Veterinaria, 1401-6257; 166 (2004).

2Costa MC, Weese JS. “The equine intestinal microbiome”. Animal Health Research Reviews 13(1); 121–128.

3Al Jassim RAM, Andrews FM (2009). “The bacterial community of the horse gastrointestinal tract and its relation to fermentative acidosis, laminitis, colic, and stomach ulcers”. Veterinary Clinics of North America: Equine Practice 25: 199–215.

4Perkins et al. “Equine Stomachs Harbor an Abundant and Diverse Mucosal Microbiota”.

5Ericsson AC et al. “A Microbiological Map of the Healthy Equine Gastrointestinal Tract”.

6Venable EB. “Role of the gut microbiota in equine health and disease”.

7Proudman CJ et al. “Characterization of the faecal metabolome and microbiome of Thoroughbred racehorses”. Equine Vet J. 2015 Sep;47(5):580-6. Epub 2014 Sep 29.

8Respondek F, Goachet AG, Julliand V. (2008) “Effects of dietary short-chain fructooligosaccharides on the intestinal microflora of horses subjected to a sudden change in diet”. J Anim Sci 86, 316–323.

9Carman JA et al. “A long-term toxicology study on pigs fed a combined genetically modified (GM) soy and GM maize diet”. Journal of Organic Systems, 8(1), 2013.

10Xie H. 2010. “Treatment of Diarrhea in hospital settings”. Personal communication.

11Mullen KR, Yasuda K, Divers TJ, Weese JS. (2016). “Equine faecal microbiota transplant: Current knowledge, proposed guidelines and future directions”. Equine Vet Educ. doi:10.1111/eve.12559.

12Sahagun AM, Vaquera J, Garcia JJ, Calle AP, Diez M, Fernandez N, Loro JF, Portilla HO, Sierra M. “Study of the protective effect on intestinal mucosa of the hydrosoluble fiber Plantago ovata husk”. BMC Complement Altern Med. 2015; 15: 298.


*This article has been peer reviewed.