Why Is My Horse Grinding or Showing Its Teeth?
By Dr. Zubair Khalid, DVM, MS, PhD ·
Horses grind their teeth for several reasons, and the meaning depends on the rest of the face and body. A horse that grinds while eating, acting colicky, or losing weight is likely in pain, while a horse that curls its lip after smelling something is showing a normal flehmen response. This article is educational and is not a substitute for veterinary diagnosis or treatment.
Quick Answer
- Teeth grinding (bruxism) in a horse that is also drooling, quidding, dropping feed, or losing weight points to a dental or mouth problem that needs a veterinary exam [1].
- Grinding that happens alongside pawing, rolling, flank watching, or going off feed points to abdominal pain (colic) and needs a veterinarian right away [2].
- A horse that lifts its head, curls its upper lip, and holds the pose for a few seconds after smelling something is doing a flehmen response, which is normal.
- A horse that pins its ears, wrinkles its nose, and shows its teeth at another horse is making a threat face, not grinding.
- Any new, repeated grinding in an adult horse deserves a call to your veterinarian, because horses hide mouth pain well and often keep eating until the problem is advanced [1].
What Teeth Grinding and Tooth Showing Actually Look Like
Owners often use the same words for three different behaviors. Sorting them out is the first step.
True teeth grinding (bruxism)
True bruxism is a repetitive masticatory muscle activity, meaning the horse clenches or grinds its teeth together over and over [3]. You may hear a rhythmic crunching, squeaking, or scraping sound when the horse is not eating. The jaw may shift side to side. The horse may do this while standing in the stall, under saddle, or during a veterinary exam.
The flehmen response
A horse that smells something interesting (urine, a new feed, another horse's droppings) may lift its head, curl its upper lip back, and hold that pose for several seconds. This is called the flehmen response. It pulls scent across a special organ in the roof of the mouth. It looks like a grin, but it is a normal behavior and not a sign of pain.
The threat face
A horse that flattens its ears, wrinkles its nose, and bares its teeth at a herdmate or at you is communicating a warning. This is a social signal, not bruxism. The mouth may open, but there is no rhythmic grinding. Give the horse space and do not punish the behavior.
Why Is My Horse Grinding His Teeth? The Main Causes
The list below separates the common pain-related causes from the less common ones. The table gives you a quick way to sort what you are seeing.
| Cause | Typical clues | How urgent |
|---|---|---|
| Dental disease (sharp points, worn or broken teeth, malocclusion) | Quidding, dropping feed, slow eating, weight loss, head tilting while chewing, bad breath | Call your vet within a few days, sooner if the horse stops eating [1] |
| Gastric or abdominal pain (colic) | Pawing, rolling, flank watching, going off feed, restlessness, bruxism | Emergency, call now [2] |
| Oral ulceration or a foreign body in the mouth | Drooling, dropping food, reluctance to drink cold water, swelling on the face or jaw | Same day [1] |
| Pain elsewhere (musculoskeletal, back, saddle fit) | Grinding under saddle only, resistance to work, head tossing | Routine visit, mention it to your vet |
| Stress, stall confinement, or feed-related frustration | Grinding at feeding time, no other signs, normal appetite and weight | Routine visit |
| Neurologic disease | Grinding plus behavior change, circling, head pressing, seizures | Emergency |
Dental disease is the most common pain-related cause
Horse teeth keep erupting throughout life to replace the wear from constant grazing [1]. When teeth do not wear evenly, sharp enamel points and uneven surfaces develop. A horse may then avoid using a painful tooth, swallow feed before chewing it, and develop indigestion, colic, or choke as a result [1]. Unchewed grain can show up in the manure. The classic signs of dental disease include slow or difficult feeding, reluctance to drink cold water, pausing while chewing, holding the head to one side, and quidding (forming a ball of feed and dropping it) [1]. If your horse shows any of these along with grinding, a dental exam is the priority. You can read more about routine care in Horse Dental Care and Floating Teeth.
Colic and gastric pain
Bruxism is a recognized sign of abdominal pain in horses. In one reported colic case, the horse showed anorexia, bruxism, restlessness with rolling, pawing, dehydration, flank watching, and abdominal distension [2]. If your horse is grinding and also acting uncomfortable, treat it as a colic emergency. Do not wait to see if it passes.
Oral pain from ulcers, wounds, or foreign objects
A cut tongue, a wire or stick lodged in the cheek, or an ulcerated mouth can all cause grinding. These horses often drool, drop food, or refuse to eat. A veterinarian needs to look inside the mouth with a speculum and light.
Pain under saddle
Some horses grind only when ridden. Dental malocclusion has been studied as a possible factor in rideability, though one controlled trial in stallions found no correlation between the dental malocclusion score and the rideability score before treatment [4]. That does not rule out mouth pain as a cause of grinding under saddle. It means the relationship is not simple, and a full exam is still worthwhile.
Stress and stable behavior
Some horses grind when bored, hungry, or stressed by stall confinement. This is a diagnosis of exclusion. Your veterinarian should rule out pain first.
Neurologic causes
In dogs, bruxism while awake has been linked to forebrain lesions in a small case series [3]. The same link has not been established in horses, but sudden grinding with behavior changes, circling, or head pressing warrants a neurologic workup.
Red Flags That Mean Emergency
Call your veterinarian immediately if you see any of these:
- Grinding plus pawing, rolling, flank watching, or going off feed (possible colic) [2]
- Grinding plus a swollen jaw, facial swelling, or a wound near the mouth
- Grinding plus drooling, inability to swallow, or feed coming out of the nostrils
- Grinding plus weight loss, quidding, or grain in the manure [1]
- Grinding plus reluctance to drink cold water [1]
- Grinding plus behavior change, circling, or head pressing
- Any horse that stops eating entirely
What You Can Safely Do at Home While You Wait
You cannot fix bruxism at home, but you can keep your horse comfortable and give your veterinarian better information.
- Remove grain and hard feed if the horse is quidding or dropping food. Offer soft, soaked feed instead.
- Offer room-temperature water. Cold water can be painful for a horse with dental disease [1].
- Watch and write down what you see. Note the time of day, whether the horse is eating, and whether the grinding happens at rest, under saddle, or at feeding time.
- Check the manure for whole or partially chewed grain [1].
- Do not put your hand in the horse's mouth. A painful horse can bite down hard, and you can be injured.
- Do not give any medication unless your veterinarian prescribes it. Your vet will calculate the dose from your horse's weight and health.
- Keep the horse in a safe, quiet area if colic is suspected, and do not let it roll unsupervised if it is trying to roll violently.
If you are also managing a dog with similar signs, the same logic applies to pets. See Why Is My Dog grinding teeth? Bruxism Dental Pain and GI Nausea for a comparison.
What Your Veterinarian Will Check and Test
Your veterinarian will start with a full physical exam, including a careful look at the head, jaw, and mouth. A speculum and light let them see the cheek teeth, which are where most problems hide.
Dental exam and imaging
The vet will look for sharp enamel points, broken or missing teeth, uneven wear, and malocclusion. Sharp enamel points and the steep angle of the chewing surface are well-recognized problems in equine cheek teeth [5]. If the exam suggests a deeper problem, your vet may recommend radiographs (X-rays) of the skull or an oral endoscope.
Colic workup
If colic is suspected, your vet will check heart rate, gut sounds, hydration, and rectal palpation. In the reported colic case, treatment included intravenous fluids, a drug to relieve intestinal spasm, a pain reliever, omeprazole, sodium bicarbonate, and an antibiotic, with symptoms resolving within 12 hours [2]. Your veterinarian will choose treatment based on your horse's specific findings.
Other tests
Depending on what the exam shows, your vet may check for gastric ulcers, run bloodwork, or evaluate the horse under saddle. If a congenital malformation such as wry nose is suspected in a foal, the workup is different and may involve surgical planning [6].
Prevention and Monitoring
Regular dental care is the foundation. Horses need preventive dental treatment throughout their lives because their teeth keep erupting and wear unevenly [1]. Most adult horses benefit from a dental exam at least once a year, and some need it more often.
Watch for early signs between visits:
- Slow eating or pausing while chewing [1]
- Quidding or dropping feed [1]
- Weight loss or loss of condition [1]
- Reluctance to drink cold water [1]
- Grain in the manure [1]
- Head tilting while eating [1]
- New grinding, especially under saddle
If you notice any of these, call your veterinarian. Catching dental disease early is easier on your horse and your wallet. For a deeper look at diagnosis and treatment options, see Equine Dental Conditions: Diagnosis and Treatment.
Limitations and When to Contact a Veterinarian
This article cannot tell you what is causing your horse's grinding. Only a veterinarian who examines your horse can do that. Individual cases need a veterinarian.
Call now (emergency) if your horse is grinding with colic signs, cannot swallow, has facial swelling, or is in distress [2].
Call the same day if your horse is drooling, quidding, dropping feed, or refusing to eat [1].
Call for a routine visit if the grinding is new but your horse is eating, drinking, and acting normally. Mention the grinding when you schedule so the vet can plan a dental exam.
Frequently Asked Questions
Is teeth grinding in horses always a sign of pain?
No. Some horses grind from stress, boredom, or stable frustration. However, pain is common enough that any new grinding should be checked by a veterinarian before you assume it is behavioral.
Can a horse grind its teeth from colic?
Yes. Bruxism is a recognized sign of abdominal pain in horses. In one reported case, a horse with colic showed bruxism along with rolling, pawing, and going off feed [2]. If you see these signs together, call your veterinarian immediately.
What is the difference between a flehmen response and teeth grinding?
A flehmen response is a brief, normal behavior where the horse lifts its head and curls its upper lip after smelling something. Teeth grinding is a repetitive jaw movement that produces a crunching or scraping sound. One is communication, the other is a physical action.
Should I float my horse's teeth if it is grinding?
Floating is a dental treatment that should be done by a veterinarian after an exam. Grinding alone does not tell you whether floating is needed. Your vet will look for sharp points, uneven wear, and other problems first [1][5].
Can grinding teeth affect my horse's riding performance?
It might. One controlled trial found no correlation between dental malocclusion scores and rideability scores before treatment in a group of stallions [4]. That does not mean mouth pain never affects performance. If your horse grinds only under saddle, have a veterinarian examine the mouth and check saddle fit.
Related Articles
- Why Is My Dog grinding teeth? Bruxism Dental Pain and GI Nausea
- Horse Dental Care and Floating Teeth
- Why Is My Dog Coughing And Honking
- Equine Dental Conditions: Diagnosis and Treatment
- Why Does My Dog Have A Honking Cough
- Why Is My Dog Coughing Honking
References
- Dental Disorders of Horses - Horse Owners. Merck Veterinary Manual.
- Chronic spasmodic colic management in a thoroughbred horse: A case report from Bangladesh. Open veterinary journal, 2025.
- Bruxism in awake dogs as a clinical sign of forebrain disease: 4 cases. Journal of veterinary internal medicine, 2022.
- Evaluation of the effects of performance dentistry on equine rideability: a randomized, blinded, controlled trial. The veterinary quarterly, 2017.
- A Computerized Simulation of the Occlusal Surface in Equine Cheek Teeth: A Simplified Model. Frontiers in veterinary science, 2021.
- Correcting Campylorrhinus Lateralis in a Foal by Bone Distraction: A Case Report. Journal of equine veterinary science, 2020.