Why Can’t Horses Throw Up?

One of the fascinating things about horses is that they can’t vomit. Weird but true! But why can’t horses throw up?

Horses can’t vomit because their digestive system doesn’t allow them to. Horses digest food in a very different way to humans, which is why you will never see a horse throwing up. Let’s take a look at horse digestion and find out why horses can’t vomit!

Why Can’t Horses Vomit?

Now it might be a disgusting subject, but today we are talking all about vomit! To understand why can’t horses throw up, first we need to understand what happens when we vomit.

Throwing up, or vomiting is a complicated action of the digestive system. Vomiting occurs when food is expelled from the stomach, up the throat, and out through the mouth. To do this the sphincter which keeps food inside the stomach must open, to allow food to exit the stomach.

In horses, this sphincter is much more tightly closed, and it is almost impossible for it to open in response to pressure from the stomach. Basically, it is a one-way valve – food and water can enter the stomach, but it is very difficult for it to leave the same way!

Why Can’t Horses Vomit

There are other reasons why horses can’t vomit. The location of the horse’s stomach is deep within the rib cage. This means it cannot be squeezed by the diaphragm to push food out of the stomach.

Another factor is the location of the esophagus – the tube which connects the mouth to the stomach. In the horse, when the stomach is full it presses on the esophagus, making it difficult for food to pass through.

So now you understand why can’t horses throw up, let’s take a look at the problems this could cause for our equine friends.

What Happens When Horses Can’t Vomit?

The fact that horses can’t vomit doesn’t normally cause them any problems. The digestive system of a horse is designed for them to eat ‘little and often’. This is perfect for an animal which spends all day grazing or nibbling at hay.

Animals which vomit – including humans – normally do so because they have eaten something their digestive system wants to get rid of. We are also sometimes sick because of a virus or other infection.

The natural instincts and highly sensitive taste receptors of a horse mean they very rarely eat anything poisonous. Food poisoning is very uncommon in horses. And if they get an infection or virus, this is more likely to cause diarrhea than make the horse vomit.

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However, there are times when it would be useful for a horse to throw up. The main example is when a horse is suffering from colic.

Colic is a painful problem of the horse digestive system. Sometimes when a horse has colic the intestines will become blocked, stopping food, liquid, and gas from passing through. When this happens the stomach begins to fill with gas, which cannot be released.

If this happened to a human, we would be able to burp or throw up to release the gas and food material. But as a horse cannot vomit, the gas builds up a huge amount of pressure in the stomach and intestines. This is very painful for the horse and can sometimes be fatal.

It is for this reason that a horse suffering from colic is regarded as an emergency. Most horses with colic can be cured with medical treatment. However, some horses will need an operation to remove the blockage and repair damaged intestines.

What Does It Mean If A Horse Is Throwing Up?

You may sometimes hear that people have seen a horse throwing up. Although it is impossible for a horse to vomit in the same way other animals can, there are two reasons why someone might think a horse is being sick:

  • Choke

Sometimes horses will suffer from a condition called choke. This is when food material gets stuck in the esophagus, and the horse cannot swallow it.

When a horse has choke, nothing can pass down the esophagus past the blockage. However, some horses may continue to try to eat and drink, and the food and water will come back out of the mouth or nostrils. Horses also continuously produce large amounts of saliva, which they are unable to swallow because of the blockage.

If you ever see a horse with choke, it will most likely have a runny mixture of chewed food, water, and saliva coming from both nostrils. The horse may also make strange gulping noises and arch its neck to try and clear the blockage.

Some horses can clear the blockage themselves, but most horses with choke will need treatment from a veterinary surgeon. While you are waiting for the vet all food should be taken away from the horse to stop the choke from getting any worse.

  • Spontaneous Gastric Reflux

If a horse has a very severe case of colic, it may do something called spontaneous gastric reflux. Remember how we said that sometimes when horses have colic they get a buildup of food, liquid, and gas in the stomach and intestines? When this occurs there are two things that could happen – the stomach could rupture, or the horse could have spontaneous gastric reflux.

The immense pressure in the stomach forces the sphincter open, allowing the stomach contents to enter the esophagus. The pressure is so great that this smelly liquid will be forced all the way up the esophagus, and out through the horse’s nostrils or mouth.

This will give some temporary relief to the horse, but the stomach will quickly fill up again unless the blockage in the intestine is removed. If you see a horse that you suspect has spontaneous gastric reflux it is very important to get veterinary help as quickly as possible.

Spontaneous Gastric Reflux


So, as we’ve learned, horses are not able to vomit because of their unique digestive system. However, sometimes food material can be regurgitated from the stomach if the horse is very ill with colic. This is called gastric reflux.

We’d love to hear about your experiences – have you ever seen a horse which you thought was vomiting? Or maybe you have a question about why can’t horses throw up? Add a comment below this post and we’ll get back to you!

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