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Dog Vomiting Blood: A Step-By-Step Guide

We know that your dog means the world to you. At Honest Paws, we are all pet lovers and dog owners. For that reason, we understand how heart-wrenching it can be when your dog isn’t feeling quite like themselves.

Furthermore, we understand how terrifying and worrisome it can be to see your dog vomiting blood. It’s hard to not go into a full-on panic mode when discovering something like bloody vomit, however, try to remain calm.

There are a number of different reasons why your dog may be vomiting blood, and it’s imperative to figure out the underlying causes in order to treat it properly and effectively.

A proper veterinarian diagnosis will be necessary in order to figure out exactly what is wrong with your pup. We don’t have to tell you that it’s not normal for your dog to throw up blood, but the faster you get a diagnosis, the better chance Fido has for a full recovery.

In this article, we hope to inform our readers of what may be causing the bloody vomit, and how to proceed in getting your dog the best care possible.

Dog Vomiting Blood

What is Hematemesis - An Overview 

Hematemesis is the medical term for a dog vomiting blood. There are a number of potential causes for vomiting blood (hematemesis). Blood in your dog's vomit may be the result of a disruption in the esophagus.

The esophagus is the tube that connects the stomach with the mouth. Another potential reason for blood in your dog's vomit is an irritation of the intestines or the stomach. This irritation can, therefore, lead to inflammation, bleeding internally, and the expulsion of blood through vomiting.

Furthermore, A relatively common causes of blood in vomit is due to the ingestion of a foreign object. This foreign body causes inflammation or injury to the mouth, lungs, stomach, or another organ. When the foreign object is thrown up, it is often accompanied by blood.

Depending on the source of the problem, hematemesis can affect several different parts of the dog's internal system. For example, the gastrointestinal system may be affected due to the ingestion of a foreign body, inflammation, trauma, or an ulcer.

The cardiovascular system may also be affected if a hemorrhage is occurring. Additionally, if your dog has a clotting disorder, the stomach and/or intestines are often affected. All of these conditions among others can ultimately lead to hematemesis.

Symptoms of Hematemesis in Dogs 

Obviously, the primary symptom of hematemesis is the presence of blood in vomit. But what pet parents may not know is that the blood can appear in several different forms.

The blood may be fresh blood, digested blood (which resembles coffee grounds), or formed clots. Additional symptoms often include a lack or loss of appetite, stomach pain, and black tarry diarrhea (called melena).

Your dog may also be suffering from anemia (a low red blood cell count), a rapid heart rate, a heart murmur, and overall weakness.

Dog Vomiting Blood

What It Means if Your Dog is Throwing Up Blood 

Now, let's get down to the specifics.

The most harmless explanation for your dog vomiting blood is that they cut their mouth while chewing on an object such as a bone, or while playing with another dog.

However, a dog vomiting blood likely means internal bleeding. Furthermore there also conditions that are far more severe that also cause blood in the vomit such as the parvovirus infection as well as cancer.

We don’t want to scare our readers any more than they probably are, but we do want to stress that it is paramount to see a vet in a timely manner if you find blood in your dog’s vomit.

Blood in Mucus 

Pet owners will also want to learn to differentiate and recognize what kind of blood they are finding in their dogs vomit. If you find vomit that is high in mucus and blood, it likely means that the stomach and/or upper intestines are bleeding, ulcerated, or inflamed.

When the blood is dark red or tarry, it usually means that there are issues in the dog's lower intestine. This dark red, tarry blood also typically smells bad.

A diagnosis from your vet will be necessary to determine the source of the blood unless it is obvious to the pet owner. Once you are at the vet, they will likely ask you a series of questions including all of the things that your dog may have gotten into and eaten.

Provide your vet with all of the information that you possibly can. This will help with a timely diagnosis and development of a proper treatment plan.

Additionally, bring a sample of the vomit to your veterinarian. This will also help speed up the diagnosing process. Be prepared for a slew of blood tests. It may seem extensive but it's necessary.

Causes of Dog Vomiting Blood 

There are many reasons why your dog may be throwing up blood. While a proper diagnosis from a veterinarian is mandatory in the majority of cases, we hope to provide our readers with details as to the possible causes of the bloody vomit.

The first step in figuring out what is causing the bloody vomit is to recognize how the vomit appears. If the blood is fresh, it will typically be bright red. The blood it may look like red streaks or specs.

You may also find bright red clots in the vomit. If the blood is older or has begun to digest in the stomach, it will be darker. Partially digested, older blood typically looks like dark coffee grounds.

It is important to note the color of the blood because the color itself will help allow the vet to diagnose how long the bleeding has been going on and what part of the dog’s digestive tract is bleeding.

Typically, bright red vomit is a sign that the bleeding is occurring in the mouth, throat, esophagus, stomach, or upper intestines.

Dark red blood typically means that the bleeding is occurring deep in the intestines. Dark red blood may also mean that the dog has a stomach ulcer.

Furthermore, when your dog vomits from drinking water too fast or eating as if it's a marathon race, the vomit should either be clear (water) or simply a regurgitation from the food source.

Now we aren't saying that this is normal, your dog shouldn't be vomiting on a regular basis, but it's a clear source. If your dog is vomiting regularly without explanation, it is important to seek veterinary intervention regardless of whether or not blood is present.

Just because there isn't blood in your dog's vomit doesn't mean there may not still be an underlying issue that needs to be addressed.

Chewing on Bones 

We want to start off by saying that we aren’t exactly advocates for dog bones. Bones, and other animal byproducts such as rawhides, can cause loads of issues for Fido’s digestive tract.

Nevertheless, dogs have been chewing on bones since long before they were domesticated, household family members and we understand that some of our readers may purchase bones for their dogs presently. We just want everyone to be aware of the potential dangers.

If the bones that your dog is chewing on happened to shatter, they will typically break into sharp pieces. While many of these sharp pieces will dissolve due to the dog's stomach acid, they do have the potential to puncture the stomach and/or intestines.

This can cause a slew of problems, most severe being peritonitis. Peritonitis occurs when bacteria leaks through a hole in the intestines. In the majority of cases, peritonitis is life-threatening.

If your dog vomits blood after eating a bone, it may be due to a minor cut in their mouth from the shattered, sharp pieces of bone.

However, it is also possible for these tiny fragments to get stuck in the dog's intestines, stomach, and/or throat. Depending on where the bone gets stuck and the degree of the blockage, emergency surgery may be necessary.

Dog Vomiting Blood from Chewing on Bones

Ingesting Foreign Objects 

All dogs seem to love getting into things that they shouldn’t. Most often, if something smells good, your dog will take a bite. This is known as a dietary indiscretion.

The most common cause of dogs vomiting blood is after they eat something that they shouldn’t have. This often occurs with puppies but trust us when we say that dogs of all ages love trash.

Bloody vomit can be the result of eating just about anything that’s inedible. For example, socks, jewelry, tennis balls, paper, coins, you get the idea.

Another cause of bloody vomit is if the dog ingests something poisonous such as garlic. There are a number of toxins that damage the dog's red blood cells if a certain amount is ingested.

This type of poisoning will likely cause the dog to vomit blood once digesting the toxins. 

Antifreeze Poisoning 

Vomiting blood is an early sign of antifreeze poisoning. A scary and little-known fact is that less than 3 ounces of antifreeze is enough to poison a medium size dog.

Even with immediate treatment, antifreeze poisoning is life-threatening and even deadly. For this reason, if you have any reason to believe that your dog has ingested antifreeze, it is imperative to seek emergency veterinary treatment straight away.

Dog Vomiting Blood from Ingesting Anti-Freeze


One of the deadliest diseases among dogs and puppies is parvovirus. Unfortunately, a dog vomiting blood is a symptom of the deadly virus.

Therefore, for this reason among others, it is critically important to seek veterinary attention straightaway if your dog is throwing up blood.

If your dog gets parvovirus, they will become extremely sick very quickly. There is no cure for parvovirus.

But with aggressive emergency treatment, survival is possible. However, the chances of survival reduce when bloody vomit begins.

Stomach Ulcer 

We previously mentioned the importance of being able to recognize differentiations in your dog's vomit. If your dog's vomit looks like coffee grounds, it is typically a sign of a stomach ulcer or bleeding in the stomach.

Humans and dogs alike can suffer from stomach ulcers and if you’ve ever had one, you know how painful they are. Stomach ulcers are sores on the inner lining of the stomach.

Often times it is difficult to treat and heal a stomach ulcer because of the fact that it will constantly be re-injured by acidic food that is being digested.

Stomach ulcers may be caused by medications such as painkillers, aspirin, and/or steroids. The ulcers lead to chronic inflammation and bleeding, including bloody vomit.

Bacterial Infection 

Another possible reason that your dog is vomiting blood is due to an underlying bacterial infection.

Food poisoning or bacterial infections with salmonella, E. coli, Campylobacter, clostridia, and other forms of bacteria will more than likely lead to bloody vomit.

Bacterial infections in dogs have similar symptoms as bacterial infections in humans. These symptoms include appetite loss, fatigue, generalized pain, bloody diarrhea, and/or fever, as well as bloody vomit. Again, a veterinarian will need to diagnose the bacterial infection to ensure proper treatment. 

Food Allergy 

We don’t have to tell you that dogs are highly sensitive creatures. Just like humans, dogs can be allergic to their food. Vomiting is a typical response to a food allergy.

The vomiting usually develops quickly after switching to a new food. However, it’s also possible for your dog to gradually become allergic to food, even if they’ve been eating it for years.

If the dog’s food allergy is severe, they may vomit blood. Food allergies also cause bloody stool and severe abdominal pain. Food additives are the cause of some of the most common food allergies.

These additives include sweeteners, preservatives, flavorings, etc. Other typical food allergies include wheat, dairy, eggs, corn, and fish.

Unfortunately, there’s no easy way to figure out exactly what your dog is allergic to other than trial and error.

While it can be time-consuming and a bit costly, it’s worth figuring out what your pup is allergic to. Once allergens are removed, you can base their diet on nourishment that won’t cause an upset stomach.

Dog Vomiting Blood from Food Allergy

Blood-Clotting Disorders 

Bloody vomit that is caused by internal bleeding is often due to an underlying blood-clotting disorder.

It may also be due to an underlying condition such as liver failure or cancer. Furthermore, if the dog is exposed to pesticides and toxins, additional problems may arise that ultimately lead to blood clotting and therefore vomiting blood.

Again, even more reasons why it is so important to make an appointment with your veterinarian at the first sight of blood in your dog’s vomit.


Some parasites, such as hookworms, chew holes in the intestines of dogs. These parasites attach themselves to the intestines and feed on blood.

If there are a high number of parasites within the dog's intestinal tract, vomiting blood will likely occur. The dog will also likely have bloody stool.


Bloody vomit may also be a symptom of cancer. While there are many forms of cancer in dogs, the cancer most associated with bloody vomit is cancer of the stomach.

Esophagus tumors and stomach tumors also have the potential to cause bloody vomit. While vomiting blood is definitely not the only symptom of cancer in dogs, it’s usually one of the first to arise.

Bilious Vomiting Syndrome 

If Fido is suffering from the flu or from a virus, it’s likely that the dog owner will start to see specks of blood in the vomit.

The specks of blood occur when persistent vomiting (known as Bilious Vomiting Syndrome) causes blood vessels to break in the stomach.

The bright red blood will appear as minor bleeding and typically happen on an empty stomach.

Long-Term Stomach Inflammation 

Chronic gastroenteritis, or long-term stomach inflammation, is another cause of bloody vomit.

The bleeding occurs due to intermittent vomiting from inflammation of the stomach lining. The inflammation of the stomach lining is typically due to autoimmune diseases, metabolic or endocrine diseases, hyper-acidic syndromes, or other conditions.

Hemorrhagic Gastroenteritis (HGE) 

Sometimes the bloody vomit and accompanied bloody diarrhea seem to come out of nowhere. One of the reasons for this is the disease, Hemorrhagic Gastroenteritis (HGE).

The vomiting and diarrhea typically start with mucus and bile and then become bloody as the vomiting and diarrhea continue. HGE can be especially dangerous for small dogs as the loss of fluids can lead to kidney failure and dehydration.

Even with extensive research, experts are still not fully aware of the main cause of HGE. However, we do know that factors such as stress, anxiety and dogs, allergic reaction’s, and dietary changes can all contribute to HGE.

Other Health Issues 

Additionally, liver disease, kidney disease, spleen disease, and pancreas disease can all lead to bloody vomit.

Additional symptoms that generally accompany these diseases include loss of appetite, generalized weakness, abdominal pain, diarrhea, weight loss, and/or excessive thirst.

Blood in Vomit - What To Do 

We want to reiterate that while seeing blood in your dogs vomit may cause you to panic, try to stay calm.

Gather as much of the bloody vomit that you can and put it in a plastic bag to take with you to the vet's office.

Additionally, consider all possible things that your dog may have consumed that they shouldn’t have as well as any dietary changes or new components in your dog's life (i.e. moving homes, new interactions with other dogs, etc.)

The more information that you’re able to provide your vet with, the more efficiently a diagnosis can be made. For the vast majority of conditions associated with bloody vomit, a timely diagnosis is absolutely imperative.

How to Diagnose A Dog Throwing Up Blood 

As we have mentioned seemingly countless times in this article, making an appointment with your veterinarian is the best and most efficient way to find out why your dog is vomiting blood.

We want to warn our readers that the diagnosis may not come easily. Depending on the underlying cause of the bloody vomit, your veterinarian will likely need to do a series of tests.

These tests include a complete blood count, an organ screening, fecal analysis, Blood clot profile testing, x-rays, among others.

While the testing will be extensive, the best chance for your dog to make a full recovery is for them to receive a diagnosis immediately.

Dog Vomiting Blood: The Bottom Line

At the end of the day, we know how scary it can be to see blood in your dog’s vomit. No one said that being a pet owner was going to be easy.

Yet, when problems arise, it can be incredibly frustrating and heart wrenching for a dog owner.

Not knowing what to do and being unsure of what is causing the problem can be beyond stressful.

However, recognizing that there is a problem is the first step in fixing it. We cannot stress enough that if you see unexplainable blood in your dog’s vomit, do not delay.

While simple mouth abrasions may heal on their own, the vast majority of underlying conditions causing bloody vomit will not. We encourage our readers to talk to their veterinarian straight away.

A proper diagnosis and treatment is your dog’s primary way of getting better soon. We know this can be a worrisome time, but there is certainly hope.

Don't delay in getting your pup the treatment they need.


Sources › Dogs › Health Problems

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