Sand colic is a term for abdominal pain in horses caused by the ingestion of sand.
Sand colic typically occurs in dry areas with poor vegetation growth. When horses forage, sand particles and other sediments (such as silt and gravel) are ingested and may remain in the large colon for long periods. 
Sand enteropathy or impaction occurs when sand accumulation damages the large intestine, leading to inflammation of the colon wall, distress or complete bowel obstruction. Without medical intervention, impaction colic can be fatal.
Acute colic is a serious condition that requires medical attention. If your horse forages in a sandy region and presents clinical signs of sand colic, contact your veterinarian immediately.
Sand Colic in Horses
When horses ingest sand particles, some of the sediment is cleared via bowel movements. However, sand can begin to accumulate in the ventral colon and cecum of the horse, negatively impacting gut motility (the movement of food through the intestines).
In extreme cases, obstipation (severe or complete constipation) from blockages may occur, and intestines can rupture. 
It is unknown how much sand needs to accumulate in the digestive tract to cause clinical signs of impaction.  Signs of sediment accumulation vary depending on the size of the horse, and some horses display no symptoms at all. 
After ingesting large amounts of sand, horses may exhibit typical colic symptoms, such as: 
- Lack of appetite
- Distressed or anxious behaviour
- Pawing at the floor
- Looking at or biting at the sides of the belly
- Lying down, standing up, rolling over
- High heart rate (over 64 bpm) or other changes in vital signs
If your horse displays signs of colic, contact your veterinarian immediately for urgent care. All forms of colic should be treated as a medical emergency.
Why do Horses Eat Sand?
Sand colic is usually attributed to incidental sand ingestion that occurs when horses are foraging in sandy regions. However, some horses may intentionally ingest sand or soil at pasture, a practice known as geophagia.
This behaviour may indicate a nutritional deficiency (such as a lack of selenium or sodium in the diet) or boredom in horses.  However, further research is needed to understand the factors that cause geophagia.
Both wild and domesticated horses have been observed to return to specific locations to ingest soil repeatedly. They may be seeking out certain minerals in the soil, but site selection does not seem to correlate with soil mineral content. 
Risk Factors for Sand Colic
Several factors increase a horse’s risk of sand colic, including feeding on the ground or in sandy paddocks, housing horses on sandy soils or keeping horses on low-quality pastures. 
Horses turned out in sandy paddocks or pastures may ingest soil while searching the ground with their lips for forages. Sand colic is most common in the southern United States (i.e. Arizona and Utah), where the soil is dry and forages are more scarce.
Horses with restricted access to forages or hay could be more likely to colic due to a lack of fiber in the diet.  Fiber is critical for gut motility and clearing ingested sand and soil from the digestive tract.
Some breeds, such as the Quarter Horse, Shetland Pony, Miniature Horse and Finnhorse, are believed to be more susceptible to sand colic. This may be related to a higher appetite in these breeds. 
Your veterinarian will conduct a differential diagnosis to rule out other conditions that may be causing symptoms of sand colic. 
Horses may experience poor performance, which can be mistaken for Equine Gastric Ulcer Syndrome (EGUS) and treated as such.
Auscultation of the Abdomen
Abdominal auscultation can accurately diagnose sand colic by using a stethoscope and listening for sand sounds in the gut.
Sand sounds vary in intensity and duration, depending on the amount of sand accumulated, with large accumulations resulting in more noise. Sand sounds are believed to occur when greater than 6.3 – 10.5 kg of sand accumulates in the colon. 
Many veterinarians can identify abnormal gut sounds associated with large amounts of sand in the colon. Coarse sands may produce more identifiable noises, making diagnosis easier.
Fecal Sand Sedimentation
Fecal sand sedimentation is a reliable diagnostic tool for sand colic or impaction in horses.
However, results can be highly variable between individual horses and fecal samples. Some horses with large sand loads do not excrete sand.
Follow these steps to conduct a fecal sand sedimentation test at home on your horse: 
- Gather a few manure balls from a fresh pile and place them in a plastic bag (avoid using manure that has touched the ground)
- Fill the plastic bag halfway with water and squeeze the manure sample to create a mixture
- Hang the bag by a corner and allow the sample to settle over several hours
Horses with a moderate to severe sand load in the digestive tract will have a substantial amount of sand settling in the corner of the bag.
If a bag is unavailable, a fecal sand test can be conducted by mixing feces with water in a bucket. 
Note that healthy horses who live in sandy areas may pass small amounts of sand in their feces without signs of physical pain. Small sand loads in the gut are common in some geographical areas and are rarely cause for concern.
If a horse shows signs of colic or diarrhea and is passing noticeable sand in their feces, call your veterinarian immediately for examination and diagnosis.
Some horses may also demonstrate clinical signs of colic without passing any sand.
Abdominal Radiography & Ultrasound
The best method to determine the severity of colonic sand accumulations is abdominal radiography.  Sand and other sediments have a distinct shadow in a radiograph, and grading systems can be used to determine the size of the accumulation. 
Radiography can also be used to assess the effectiveness of treatments or supplements for evacuating sand from the gut. 
Ultrasonography is generally accurate when ruling out sand accumulation, although it has limited use when diagnosing positive tests.  This makes ultrasound an accurate screening tool with limitations for diagnosis. 
The prognosis for sand colic varies as horses tolerate sand accumulation differently. Early medical intervention is key to successful treatment when dealing with colic.
Many mild cases of sand colic are treated with a combination of nonsteroidal anti-inflammatory drugs (NSAIDs), mineral oil, magnesium sulfate (epsom salts), dioctyl sodium sulfosuccinate and psyllium. 
Acute Sand Colic
To reduce the sand load in the gut, the colicky horse must first be stabilized. Feeds should be withheld until any emergency impaction is resolved.
Once symptoms of acute colic have subsided, the affected horse can undergo treatment to reduce sand accumulation in the gut. Treatment for acute sand colic includes: 
- Pain & inflammation control (NSAIDs)
- Fluid & electrolyte administration
- Mineral oil administration
With the help of a veterinarian, analgesics (painkillers) and fluid therapy may be administered through a nasogastric tube.
Clinical signs should begin to resolve 2-3 days after the initial treatment, and the horse’s sand load should be diminished after 3-4 weeks of treatment.  Horses with impaction that do not improve with medication may require surgery to alleviate blockages.
Psyllium is one of the only non-invasive recognized treatments for sand accumulation in the gut.  Although studies have shown mixed results, this supplement may improve sand clearance in horses. 
Psyllium husks are derived from the Plantago ovata plant and are available in powdered or pelleted form. This is the main ingredient in Metamucil, which is used to alleviate constipation in humans.
The husks are a source of soluble fibre that resembles bran and acts as a laxative in the colon. 
When psyllium comes into contact with water in the digestive tract, it swells and develops a gel consistency. This fibrous solution eases the passage of sand and increases fecal output. 
Feeding psyllium is sometimes recommended by veterinarians as a preventative measure for sand accumulation. Psyllium is thought to stimulate intestinal motility, induce peristalsis (contractions in the gut) and shorten the passage time for feed through the digestive tract. 
After feeding psyllium, horses with sand accumulation will excrete jelly-like droppings that contain moderate amounts of sand. Always ensure that supplements are being used as intended and directions and instructions are being followed carefully.
Probiotics & Prebiotics
Research shows that combining probiotic, prebiotic and psyllium treatment may increase fecal sand clearance and gut motility in horses with sand accumulation. 
This combination may also reduce irritation and inflammation associated with sand accumulation, although further research is needed.
Surgery for sand accumulation is typically conducted on an emergency basis if the horse has severe impaction or cannot pass sand with the help of treatment.
Impaction usually occurs at the pelvic flexure, which is an area of the colon that folds back on itself at a sharp angle. 
Sand and feedstuffs can get stuck in this area, fully obstructing the intestine. Sand is manually removed from the intestine during surgery through an incision.
Colic surgery is expensive and is not usually a planned procedure. Owners should always have an emergency plan for their horses.
Sand ingestion cannot be entirely prevented, but sand accumulation and risk for colic can be reduced with management practices.
Ensure your horse has adequate access to good-quality hay. Fiber-rich forages help move sand through the digestive tract. 
Provide your horse with constant access to fresh, clean water to prevent feed impaction in the intestines and promote sediment movement through the gut. Adequate hydration is important for gut motility and preventing colic.
Feed your horse 1-2 tablespoons of plain loose salt and provide free-choice loose salt at all times. Salt promotes water intake and electrolyte balance.
In rare cases, horses sensitive to sand accumulation or colic may need to be confined to a smaller sand-free paddock or muzzled to prevent sand ingestion. However, this is a last resort and other preventative measures should be implemented first.
Raised or Contained Feeders
Horses should be fed forages off the ground or from raised feeders to prevent sand from accumulating in the feedstuff. 
Rubber mats can be placed under feeding containers or forages in a paddock or at pasture to prevent accidental sand ingestion.
Horses susceptible to or at high risk of sand accumulation may be fed a preventative psyllium supplement daily for one week each month. 
This practice may prevent large amounts of sand from accumulating in the gut by promoting regular excretion. 
Sand accumulation in your horse’s gastrointestinal tract can disrupt the microbiome, cause inflammation in the intestines, and affect nutrient absorption.
If your horse tends to accumulate sand in the gut or has a history of colic, feed an equine digestive supplement to support healthy gut function and the immune system.
Mad Barn’s Optimum Digestive Health is a pelleted supplement that supports hindgut health and microbiome balance with 100% natural ingredients.
This comprehensive blend of probiotics, prebiotics, enzymes, yeast and nucleotides improves nutrient uptake and helps reduce the risk of digestive dysfunction and colic.
Consult with our equine nutritionists for further ways to support your horse’s gut health and to prevent or promote recovery from sand colic.
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