Psyllium, Sand, and Sand Colic in Horses


There’s a delightful plant called Plantago ovata, and this plant’s seeds have a shell. The outer seed housing is the psyllium seed husk, and it’s a great source of fiber. Most of us just call it psyllium.

Table of Contents


Does psyllium work?

How horses eat sand

Where does your horse collect sand in his digestive tract?

What problems does sand cause?

There are questions about the psyllium protocol

More science about psyllium and sand

Prevent your horse from eating sand.

Do chia seeds work to clear sand from horses?

Easy to read summary of what we know for sure

Go shopping


Does psyllium work to clear sand build-up from your horse?


  • MAYBE? Here’s what I know about sand, psyllium, and sand colic. Get ready.


  • There’s a lot of confusing and sometimes conflicting information out there— both in terms of actual science and anecdotal experiences of vets and horse owners alike.


  • This article is an attempt to make sense of it all! Let’s start at the beginning.


  • The general problem with sandy soil and dirt is that horses will eat it. For simplicity’s sake, let’s call it all sand. Horses ingest sand, sometimes accidentally, sometimes with purpose. Some sand may end up passing in manure, and some sand may end up camping in your horse’s belly somewhere along the intestinal tract.


horse eating on sandy pasture

This is a sand salad with some grassy greens.


How horses end up with sand in their digestive tract


  • Unfortunately, horses are not too discerning about what goes into their mouths. Most sand gets eaten when horses munch on their hay off the ground or are grazing in short pastures.


  • Horses can also pick up unsavory bits of dirt if their hay is filthy or are eating from their stall floors. Ever watch a horse just trolling the ground for every last morsel? Sure, the tasty particles are picked up, likely with some added dirt, too.


  • And some horses eat dirt to keep their mouths busy. Others eat sand and dirt because their diets lack in chew time, or nutrients, or both.


  • One vet’s account includes some information about the type of sand that horses eat. The finer, sugary sand is more likely to pass through your horse than the heavier, rougher, and larger types of sand and earth.


Where does sand collect in your horse’s digestive system?


  • Usually, any sand eaten by your horse will pass through his digestive system with relative ease. It gets mixed up with his manure. The sand and fecal balls eventually pass through. No one knows what the transit time is for this, although best guesses suggest it varies from horse to horse.


  • Horses get into trouble when some of the sand remains, creating a trap for more sand. A healthy digestive tract will sometimes clear some of the sand, but when it collects, there’s a risk of sand colic.


  • While there are some accounts of sand collecting in the small intestine, most of it seems to reside in the large colon.


bay horse rolling in field

Sand colic can happen, unfortunately.


What problems does sand cause?


  • Sometimes sand doesn’t cause any problems for horses. But when it does, here are some things that can happen.


Irritation of the intestines.


  • Sand is abrasive and will irritate the lining of the intestines. The irritated tissues become inflamed, which interferes with digestion. Horses may go off their feed, become depressed, look bloated, and generally feel lethargic. There’s abdominal pain associated with carrying around all of this sandy weight, too!


Diarrhea and weight loss.


  • Inflammed intestines create less surface area for the digestive system to absorb nutrients, water, and calories across the intestinal wall. Horses often develop diarrhea and drop weight.


  • Side note – ** diarrhea in horses is an emergency** There are many causes of diarrhea, like viruses, fevers, eating something sketchy, and stress. Repercussions of diarrhea may include colitis, spreading disease through a barn, colic, laminitis, and more. Call the vet.


  • Psyllium for horses with diarrhea can be part of the treatment plan in some cases. While it seems strange to give a horse something with a laxative effect, the psyllium helps your horse’s gut remove water, thus reducing diarrhea.


The risk of laminitis.


  • Any time the gut of a horse changes, laminitis becomes a risk with a sand disruption. The intestinal wall loses function when swollen and irritated, allowing endotoxins from the gut’s microflora to get into the bloodstream and end up in the hooves.


More information about laminitis:

Signs of Laminitis

Why laminitis happens

Risk factors for laminitis


Colic and beyond.


  • As sand starts to accumulate, a snowball effect happens. There is the additional weight for your horse’s intestines to carry around. Sand plus food can create partial and complete blockages, leading to colic and gas build-up. In some cases, twisting of the gut and even rupture of the intestinal wall may happen.


  • In many sand colic cases, it may appear to clear up with pain medications, only to return days later. Surgery is often warranted for severe cases of colic to remove large quantities of sand.


  • The sand accumulation cycle perpetuates itself. Sand irritates your horse; he reacts with swelling, creating the perfect scenario for more to accumulate. More irritation and disruption lead to more sand collecting.


More about colic:

Colic risk factors

Signs of colic in horses

Help prevent colic



manure and water in a baggie looking for sand

This is not conclusive!


How to test your horse for sand in your horse’s belly


  • There is a simple test that you can do to check for sand in your horse. HOWEVER – it’s not a complete picture and should not be used as a definitive diagnostic tool.


  • Put some fecal balls into the water in a bag or medical glove. Allow the fecal balls to soften and dissolve in the water. Sand in the manure will fall to the bottom of the bag.


  • If your cursory test reveals sand, this means your horse has eaten and passed sand. It does not tell you if sand is remaining in the belly, and it does not tell you how much sand might be staying in the gut.


  • If your cursory test does not reveal sand, you still don’t know much. There could be sand in the belly, and none is passing. You don’t know how much may be there. Or, there is no sand in the belly.



This explains the sand test. It’s mostly helpful, but not conclusive.


Get your vet onboard.


  • Your vet will need to perform some simple tasks to find a more conclusive answer for you about your horse’s situation.


  • X-rays, abdominal ultrasound, and advanced listening techniques can gauge how much sand might be in your horse’s belly. Do not rely on the “poop soup in a bag” method; it’s only part of the picture and is misleading unless your vet does further diagnostics.


How to help your horse pass sand


  • There are lots and lots of resources about how to help your horse pass sand. There’s also lots of conflicting science. Let’s wade through all of it to figure out what’s what.


The psyllium protocol – there are questions.


How psyllium works to clear sand in horses.


  • Psyllium is a laxative, a fibrous laxative. It’s commonly and incorrectly thought to clear sand by picking up particles. As psyllium gets wet, it gets a bit jelly-like. The thought is that psyllium’s jelly-like substance glues sand to it to carry out in the manure. This is only partially true.


  • What we know is that psyllium may only pick up a tiny fraction of sand on its gooey surface. The power of psyllium comes with its ability to support your horse’s gut health as a whole.


  • During digestion, psyllium works as an energy source in the hindgut, where all sorts of microbes eat fiber. When the microbes eat psyllium, they increase the levels of healthy substances like butyrate. The intestine is full of colonocyte cells, which use butyrate. When colonocytes are happy, they can repair and regenerate, improving overall gut health.


  • When the gut is happy, it has improved function – one of which is to physically move things – like sand and manure – from rooter to tooter.


  • Psyllium is the boost to help your horse’s gut get rid of the sand by itself.


horse eating from a hay net inside a tub

This hay net is secured in the tub, reducing the amount of hay that lands on the earth.


What is the best way to feed psyllium to horses for the removal of sand?


  • The technique of feeding your horse psyllium for a week out of every month is questionable, at best.


  • Many moons ago, a researcher posed the question of feeding psyllium for seven consecutive days out of every month. No scientific studies have been done to flush this question out.


  • There seem to be some unproven beliefs that horses will develop a resistance to psyllium if kept on a supplement daily.


  • BUT – I found some interesting information about this “full week” practice and this hypothesis of psyllium resistance.



“There has yet to be a research study confirming or denying the development of psyllium resistance in horses who are supplemented daily. In fact, to date, there are more studies supporting its daily use in horses than discouraging it. And after 10 years of daily use in clinical cases using the Assure products no resistance has been detected.”



  • Contrary to this, many articles from vets and experts suggest the “one week a month” method is suitable for horses at risk of collecting sand.


  • This veterinary document suggests that the horse’s gut microbiome will learn to degrade psyllium if fed 4-5 weeks continually, which means the continual method may not be the best.



psyllium husks in a small pile

Psyllium husks


Can you get psyllium wet before you feed it?


It depends on who you ask.


  • Psyllium husks will puff and become gelatinous when wet. When humans take psyllium, it’s typically powdered and mixed with water to drink. For horses, horses may not want to eat soggy, jelly-like additions to their meal.


  • On the other hand, If a horse eats psyllium husks that are not already wet, they may fully develop into their sticky selves after passing through the small intestine. This might make sand pick-up less likely to happen in the small intestine if there’s any there in the first place.


  • Clearly, this is not a perfect situation! Psyllium pellets and psyllium powders are available. Your horse will tell you which one he prefers and in what form he likes to eat it.


More science about psyllium and sand.


This article, written by a veterinarian, talks about a study where the results showed that horses untreated with psyllium passed more sand than those treated with psyllium.


  • The researchers gave horses receiving psyllium one pound a day, much more than the usual dosage recommended by most supplement companies. The real bummer about this is the lack of an official reference to the study.



Here’s another study that goes a bit deeper into psyllium for sand removal.


  • Here, researchers looked at magnesium sulfate via a nasogastric tube (feeding tube), magnesium sulfate and psyllium via a feeding tube, and feeding psyllium.


  • Results show that the horses receiving treatment via feeding tube for a few days was more effective than with eating psyllium for 10 days.


  • Magnesium sulfate alone cleared sand from 2 of 10 horses, and 3 of 12 horses cleared sand with psyllium alone.


Here’s another study, looking at the effectiveness of psyllium and/or mineral oil.


  • Here, the researchers found that more sand (measured by the amount of crude ash in the manure) passes when mineral oil and psyllium are given via a feeding tube.


And this article detailing a study, now two decades old, about psyllium doing well to clear sand from horses.


  • Of the horses studied, 63% improved sand volume after a month and 91% after two months.


And then this game-changer of a study, outlined here:


  • The horses in this study were grouped into four sections. Some received a normal amount of hay, some received more hay, some received normal amounts of hay plus psyllium once daily, and some received normal amounts of hay plus psyllium twice daily.


  • The group faring the best at passing sand was eating more than a normal amount of hay daily. Hay as sand clearing? YES – it’s been long thought of as the best way to clear sand, until the sand gets backed up and the volume is too great.


OK – at this point, things aren’t looking so good for psyllium products.


But I did find this gem, hidden far away.


  • In this study, it was found that a combination of psyllium plus pro- and pre-biotics fed for a month helped clear sand.


horse eating from hay net attached to a tree outside

Outdoor dining is perfect if there are mats or a tub underneath to catch spilled hay.


How can you prevent your horse from ingesting sand?


  • Preventing your horse from eating sand lands squarely in the “creative barn management” category! These techniques mimic the notion of your horse eating as naturally as possible for as long as possible. Win – win.


  • Use slow feeders, like hay nets. Hay nets are affordable, but there are other types of slow feeders available, too.


  • Feed your horse over clean mats instead of shavings or the earth. You could use big tubs instead of rubber mats if that works better for you. It’s easy to modify a large tub to strap in a hay net. Add a drain hole if the tub will be outside. Tubs don’t need sweeping, so that makes life a bit easier for you.


  • Don’t let your horse graze on short grass or patchy grass. Not only is this damaging to the root system of your pasture, but your horse also noms down on sand.


  • For sloppy eaters that dribble food all over the place and then graze to pick it up, change the location of things. Hang door feeders and hay nets outside of stalls and fences, so he won’t be able to graze his droppings.


  • If your horse’s hay is dusty and dirty, you can steam or soak it. Soaking hay is beneficial for metabolically challenged horses, as well.


  • Touch base with your equine nutritionist to verify that your horse’s diet is balanced and he’s not missing anything.


Chia seeds vs. a psyllium product for sand clearing in the horse’s digestive tract.



  • There’s seems to be some new MARKETING that suggests chia seeds can clear sand. There is ZERO SCIENCE done on this topic. ZIPPO.


  • Does this mean that chai seeds can or can’t clear sand? No idea. But it’s a healthy reminder that just because something is printed on an unregulated, nutraceutical supplement product doesn’t make it true.


Let’s sum this up with some highlights.


  • I’ll let you know when I find some evidence that supports psyllium alone for clearing large amounts of sand, and will update this article accordingly.


  • It’s worth noting that almost all of the studies examined horses that already had large volumes of sand, not normal horses that may need help preventing sand accumulation.


  • The only way to understand how much sand a horse is lugging around involves your vet. Get x-rays and other formal diagnostic tests.


  • Let’s suppose your vet finds an alarming amount of sand. A combo treatment of psyllium and something else administered via tube may be helpful – your vet can guide you.


  • Psyllium is not harmful to horses.


  • Preventing sand ingestion is much better than trying to clear sand. If you are remotely concerned, add mats, use tubs, and add slow feeders to your horse’s life. The benefits of these tactics go beyond just sand in bellies.


  • Horses will proper gut health can often clear sand themselves if it’s not allowed to accumulate. This is good news!



PHEW! You made it through this glorious piece of confusing-ness. Well done.



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