Why Is My Dog Vomiting?

Stephanie Lantry, DVM
By Stephanie Lantry, DVM on Nov. 3, 2020

There’s nothing that can get a pet parent moving quite like the sound of a dog vomiting or about to vomit. It’s a sound that all pet parents recognize and hate to hear.

So, what causes dog vomiting?

Dogs vomit for many reasons. Some of the reasons are nothing to worry about, but sometimes, vomiting is a sign of a serious health problem that needs immediate veterinary care. 

Learning to tell the difference can be tricky, but it’s important to know why dogs vomit, when you should be concerned, and what you can do to help.

This guide will break down the causes of dog vomiting, help you identify dog vomit types, and explain what you should do and when it’s time to call a vet.

Jump to a section here:

Is It Dog Vomiting or Regurgitation?

One important thing to keep in mind is that dog vomiting and regurgitation are not the same thing. Think of dog vomiting as more of an “active process” and regurgitation as more of a “passive practice.”

Why do you need to know the difference? Because the causes of and treatments for the two conditions are very different, and vomiting tends to be more concerning than regurgitation.

Dog Vomiting

Vomiting occurs when the contents from the stomach and upper intestines are forcefully ejected. Dog vomit can contain yellow bile or dog food that has been partially digested, and it usually smells sour.

Vomiting may occur directly after eating or anytime thereafter. It’s usually preceded by signs of nausea, such as drooling, licking the lips, and swallowing excessively.

Some dogs may eat grass before or after they vomit, possibly to induce vomiting or protect the esophagus, because grass can cover sharp objects like bone shards when the dog vomits. it is a good idea to prevent them from eating a large amount, or it may make matters worse. 

They might also eat their own vomit. This is an instinct that dogs have that is very unappealing to us as humans, but it’s not a big problem for dogs.

Because vomiting causes dehydration, your dog might try to gulp down a whole bowl of water after vomiting. This may trigger more vomiting, so try to limit their water consumption to small amounts at a time. 

Regurgitation in Dogs

Regurgitation, on the other hand, is a mild ejection of undigested food from the dog’s esophagus, meaning that it never made it to the stomach. A major difference is that regurgitation doesn’t involve abdominal heaving.

It tends to happen shortly after eating—maybe your dog ate too much or ate too fast. Or your dog could be overly excited or stressed out.

What Does Your Dog’s Vomit Look Like?

Once you’re pretty sure that your dog is vomiting and not regurgitating, you can identify the type of vomit by the appearance of it. What the vomit looks like can help determine the causes of vomiting in dogs.

Yellow Vomit

Yellow vomit is very common when a dog has an empty stomach, and the yellow color that you see is due to bile secretions. This occurs most commonly in the middle of the night or early morning hours.

It can be caused by acid buildup, reflux, or any other systemic condition that causes nausea on an empty stomach.

White, Foamy Vomit

Vomit that is white and looks foamy can be caused by a buildup of stomach acid. The foamy appearance may be caused by the vomit coming into contact with the air or being sloshed around in the stomach before the vomiting occurs.

Clear, Liquid Vomit

If your dog is vomiting a clear liquid, it can either be caused by stomach secretions or when there is water pooling in the stomach that comes up by itself when vomited.

Often, this happens when a dog drinks while feeling nauseous and can’t even keep the water down. 

Mucus-Like, Slimy Vomit

Slimy vomit that looks like mucus occurs when a dog is drooling and it pools in the stomach in response to some major irritation. The dog relieves their nausea when they vomit up the mucus. 

Bloody Vomit (Red or Pink)

Blood in a dog’s vomit should always be taken seriously.

Blood itself causes nausea, so it is often vomited up if it pools in the upper gastrointestinal (GI) tract. If the color does not progress to red, and the vomiting is not prolonged or profuse, the pink tinge is not always a sign of an urgent situation.

However, if there are blood clots, fresh blood, or a coffee-ground appearance to the vomit, these things could indicate bleeding into the stomach or upper small intestine.

Bleeding can be a result of an ulcer, a tumor, lack of clotting, or eating rat poison. All of these conditions need treatment as soon as possible in a veterinary hospital. 

Brown Vomit

Brown vomit could just be regurgitated food from the esophagus that never made it to the stomach to be digested. Also, it can indicate that a dog ate too quickly and didn’t chew the food, or swallowed a lot of air by gulping it down.

But although brown vomit may look like it’s just regurgitated kibbles, sometimes, there can be more to it. It’s best to inspect the vomit to try to determine the nature of the contents.

Traces of blood can appear brown at times if they are not profusely bloody. Brown vomit can also be an indicator of coprophagia (eating poop)

Green Vomit

Green vomit can be caused by eating grass. It can also be due to a contraction of the gall bladder before vomiting (usually on an empty stomach), resulting in bile in the stomach. 

Worms in Vomit 

Worms and other infectious organisms can cause vomiting in dogs. If there are live worms or a large infestation, such as with roundworms, a dog may vomit them up. (More commonly, they will shed eggs that can be found in the feces, and that is the only way to diagnose them.)

Grass in Vomit

Grass is a common ingredient in dog vomit.

Dogs often eat grass when they have an upset stomach, which can sometimes induce vomiting. If they are eating grass on a regular basis, however, it is a possibility that they can be ingesting more pesticides and parasites. 

Types of Dog Vomit Infographic

Why Is My Dog Throwing Up?

There is no catchall answer for why a dog is vomiting.

Different ages, breeds, and behaviors can make dogs more prone to vomiting.

There can be external causes or internal causes, and there are many factors, including the duration, color, severity, etc., that can Influence how to respond to the vomiting.

Here is a list of possible causes of vomiting in dogs, whether it’s acute (one-time, sudden instance) or chronic (happens often over time):

  • Abrupt diet change

  • Constipation

  • Diabetes mellitus

  • Drinking contaminated water

  • Eating grass (which can be caused by something else)

  • Eating poop (coprophagia)

  • Gastritis or an upset stomach from eating garbage or spoiled food

  • Gastroenteritis (inflammation of the stomach and intestinal tract)

  • Gastrointestinal ulcers

  • Head trauma, drug side effects

  • Infections (bacterial, viral, or fungal)

Acute Dog Vomiting 

Acute vomiting is something that comes on all of the sudden and has not been going on for a long time. 

Here are some reasons why a dog may suffer from acute vomiting:

Eating Something Bad

Dietary indiscretion is something that is more common in younger dogs. From getting into the trash to eating a poisonous outdoor plant, you will usually know very quickly that your dog is sick.

If they eat an object that bounces around in their stomach but doesn’t cause an obstruction, this could turn into a chronic condition if you don’t know it is in there.

If the food they get ahold of is super fatty, it can lead to another serious stomach issue called pancreatitis.

Contagious Diseases 

Dog vomiting can be caused by certain contagious diseases as well, which are also more common in younger dogs. 

One of the causes of a dog vomiting from a contagious disease is parvovirus, which can be very serious. It’s most common in puppies that are around other dogs in group settings.

Certain breeds may be more susceptible to parvovirus, including Rottweilers, Doberman Pinschers, German Shepherds, Labrador Retrievers, and sled dogs.

Intestinal Parasites

Parasites can also cause vomiting in a dog.

Often, the dog is carrying the parasite and we don’t know it. Then, all of the sudden, they may start showing symptoms such as vomiting.

Sometimes, the actual worm is vomited up, and more often, we don’t see the worm but the eggs that can be detected in the stool sample. 

Contaminated Water

Drinking out of puddles and community drinking bowls can cause some bacterial imbalances that may cause stomach upset in dogs.

Drinking out of lakes with cyanobacterium (blue-green algae) can be deadly. The dog may first develop vomiting, but severe cases can progress to neurologic signs and death.


Vomiting can be caused by bloat. Bloat or gastric dilatation and volvulus is an acute and life-threatening condition requiring patients to be hospitalized and aggressively treated.

If the stomach fills with air and then twists on itself, it can cut off the circulation and cause the dog to go into shock. 

It is most common in large-breed and deep-chested dogs, including German Shepherds, Great Danes, Standard Poodles, and Labrador and Golden Retrievers.

Eating or drinking excessively or quickly can be a factor in developing bloat.

Chronic Dog Vomiting

A chronic condition is one that goes on for a long time, and can be constant or every so often.

Chronic dog vomiting can be frustrating if you don’t know the underlying cause. Some dogs are prone to vomiting on a regular basis. Chronic vomiting in young dogs is often due to parasites or a food sensitivity. It can also be caused by certain diseases or health issues.

Bloodwork, X-rays, ultrasounds, or biopsies are often necessary to diagnose the problem.

Here are some of the common causes of chronic vomiting in dogs.


Megaesophagus, which is a generalized enlargement of the esophagus, can be caused by a number of conditions that can affect dogs of all ages.

Some dogs can be born with the condition because that is just how their esophagus is formed. Other dogs acquire it over their lifetime due to conditions such as Addison’s disease, myasthenia gravis, or hypothyroidism.

Inflammatory Bowel Disease

Chronic vomiting also can be caused by inflammatory bowel disease (IBD). As the name implies, one may associate IBD with lower GI symptoms, but in fact, sometimes vomiting is the main symptom. 


We mentioned pancreatitis as a common acute cause of vomiting in dogs. However, some dogs suffer from chronic pancreatitis, which makes them prone to vomiting on an ongoing basis.

These dogs need to be fed a very low-fat diet without exception.

Schnauzers, Shetland Sheepdogs,  Yorkshire Terriers, Poodles, and Bichon Frisés are genetically prone to chronic pancreatitis, which can also lead to diabetes.

Do You Need to Go to the Vet if Your Dog Is Vomiting?

The most important thing to determine is when it’s necessary to bring your dog to the vet, and when it’s okay to try a home remedy or just wait for the vomiting to pass.  

If the vomiting has been going on for less than 12 hours, and your dog is perky and keeping down food and water, then it may be okay to wait and monitor the situation. 

One of the biggest dangers with dog vomiting is dehydration. When a dog becomes dehydrated, essential body functions start to break down.

It’s time to call and visit your vet if your dog:

  • Is a puppy (can become weak from dehydration or have hypoglycemia if they can’t keep calories down)

  • Is geriatric

  • Is projectile vomiting (potential sign of obstruction)

  • Tries to vomit or dry-heaving and nothing comes out (symptom of bloat, which can be life-threatening)

  • Vomits blood

  • Vomits pieces of a foreign object or an entire object

  • Is lethargic (sign that the whole body is affected)

  • Is urinating less (sign of dehydration)

  • Has a tender or enlarged abdomen (seen with more serious causes of vomiting)

  • Refuses food

  • Cannot hold down small amounts of water

  • Is showing signs of dehydration (the skin doesn’t snap back into place after being gently pulled; dry gums)

  • Has diarrhea with the vomiting (can quickly lead to dehydration)

  • Has pre-existing medical problems

  • Ate people food (to determine whether it’s cause for concern)

  • Vomits often (chronic vomiting)

  • Is losing weight from vomiting often (chronic vomiting)

  • Is declining in their appearance and overall demeanor (including weight loss, muscle mass deterioration)

Emergency Situations

The things to watch for that would warrant an urgent visit to the vet or emergency clinic include:

Vomiting accompanied by diarrhea (especially if it turns bloody)

This indicates a situation that can quickly lead to severe dehydration that could result in a need for hospitalization.

Your dog becoming lethargic after vomiting, or vomiting with shaking

This could be a result of severe abdominal pain or cramping from electrolyte imbalances. You do not want to wait too long without veterinary attention.

Your dog eating a foreign object, a known toxin, or something you suspect may be toxic (projectile vomiting could signal eating a foreign object)

If you are unlucky enough to not stop it from going down the hatch, you can inform the vet or poison hotline right away what it was and find out what actions need to be taken.

What Can You Give a Dog to Stop Vomiting at Home?

There are some home remedies that you can try if your dog is having mild vomiting and not any of the serious symptoms mentioned earlier. 

Pepto Bismol is not a preferred treatment for dogs. The concern about Pepto Bismol is that it contains salicylic acid, which is an ingredient in aspirin. We need to use this with caution, especially in dogs taking anti-inflammatories or steroids, as it could cause GI bleeding.

Pepcid AC (famotidine) and Prilosec (omeprazole) are safer options to use to help reduce acid production and acid reflux, and these often settle their stomach. 

Dog Vomiting Treatment at the Vet’s Office

In most cases of vomiting, treatment via injection is the most effective route. It is the most reliable way to guarantee that the medicine is getting into the dog’s system and to prevent further vomiting. Often, a dog will vomit up a pill, and it can’t help them if they can’t keep it down. 

Medications to Stop Nausea and Vomiting

Cerenia (maropitant citrate) is the most commonly used antiemetic (medication that stops vomiting) for dogs in recent years. It acts on a trigger zone in the brain to stop nausea, and also acts on receptors in the stomach.

Vets will often start your dog with an injection of Cerenia and then follow up with pills every 24 hours for a couple of days to make sure the vomiting has been resolved.

Reglan (metoclopramide) is less widely used but is still very helpful for motility disorders in dogs as well as megaesophagus.

Zofran (ondansetron) is also an antiemetic that’s used in a hospital setting. 

In addition to these measures, the veterinarian may also recommend feeding your dog a bland or easily digestible diet.

How to Prevent Some Cases of Dog Vomiting

Many causes of dog vomiting cannot be prevented, but some can be if you follow these rules:

  1. Don’t change your dog’s diet suddenly. Always use a gradual approach. Sudden dietary changes are a common cause of intestinal upset in dogs.

  2. Don’t give your dog toys that can be swallowed or chewed into pieces, thereby causing GI irritation or blockage.

  3. Don’t give your dog bones. These, too, are routinely implicated in vomiting episodes.

  4. Avoid table scraps. Some human foods are downright dangerous for dogs (e.g., grapes, raisinschocolatexylitolonions, garlic, chives, macadamia nuts, and high-fat items), but individuals with sensitive stomachs may not even be able to eat “safe” human foods without vomiting.

  5. Don’t let your dog scavenge for food on walks or by having access to garbage cans. “Garbage gut” is what veterinarians commonly call the gastroenteritis caused by consuming scavenged items. Scavenging also increases the risk of foreign-body ingestion and toxin exposure.

  6. Watch overly inquisitive dogs carefully. You might even want to try to use a muzzle to keep them from eating anything they might find along your walks.

Featured Image: iStock.com/NicolasMcComber

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Stephanie Lantry, DVM


Stephanie Lantry, DVM


Dr. Lantry is a Milwaukee, Wisconsin native. She knew from a very young age that she wanted to be a veterinarian and worked towards that...

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