Why Is My Dog Vomiting Blood?

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Key points

  • Bloody vomit is a relatively common condition for canines. It can be harmless in some cases and life-threatening in others;
  • Typical triggers for blood in a dog’s vomit may vary from the dog chewing on bones to cancer;
  • If you notice that your pet threw up blood, bring it to the vet immediately since this may have been caused by a condition that requires immediate, aggressive treatment;

Just like humans, our four-legged friends may vomit from time to time. While this is often harmless, most dog owners immediately become worried about their pet’s health. Sometimes, the cause of vomiting in dogs can be completely harmless – maybe your pet just ate too much grass while out on a walk. However, if the dog is vomiting bloody phlegm, it could indicate a serious illness.

Is Bloody Vomiting Dangerous for Dogs?

The medical term for bloody vomiting in dogs is hematemesis. The condition is relatively common and might be caused by various triggers such as damaged esophagus lining or irritation of the stomach or intestines. In addition, inflammation or injury in the mouth or lungs can lead to vomiting blood. In these cases, the dog will swallow blood first and then regurgitate it. Depending on the origin of bleeding, it might look fresh and bright red in color or be partially digested and, therefore, have a dark-red color, coffee ground-like texture, and a foul smell. If blood is accompanied by mucus and bile, it typically means that the dog’s stomach or upper intestines (the part of the intestinal tract connected to the stomach) are inflamed, ulcerated, or bleeding. In the worst-case scenario, the underlying reason for vomiting blood is canine cancer or parvovirus infections.

What Causes A Dog To Vomit Blood?

Foreign Bodies

One of the most common reasons for bloody vomit in dogs is a foreign body accidentally eaten by the pet. This is especially true for younger dogs who may get into the trash when unsupervised. Ingesting an old chicken carcass, jewelry, socks, or balls can upset the pet’s stomach and cause bloody vomiting.

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Eating toxic or poisonous substances can also lead to bloody vomit. For example, consuming too much garlic, which damages canine red blood cells, will make your pet throw up blood.



Many dogs are allergic to specific types of foods. Therefore, pet owners are recommended to slowly incorporate new ingredients into a dog’s diet since this might help spot potential allergies as soon as they appear. If an allergic reaction is severe, it might cause your dog to vomit blood. Products such as beef, eggs, milk, and fish are most likely to cause food allergies in dogs. Bloody diarrhea and extreme pain can also be the result of allergic reactions. Keep in mind that over time, your furry friend can even become allergic to food that has never caused issues before.

Chewing on bones

Many pet owners give their dogs bones to provide the canine with mental stimulation and clean its teeth. However, once your dog’s jaws break down bones into small, sharp pieces, they can cause a lot of damage. Although dogs usually throw up blood due to minor cuts in their mouth, sharp bone fragments can cut their stomach or intestines leading to peritonitis. In this life-threatening condition, healthy gut bacteria are introduced into the bloodstream.

Additionally, your pet might need surgery if a large bone gets lodged in the throat or blocks the intestines.

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Stomach ulcers

Dark-colored, tarry blood in vomit is usually a sign of an ulcer or internal bleeding in the stomach. Stomach ulcers are sores caused by excessive amounts of acid from the gastrointestinal system that erodes the stomach’s mucosal lining. As a result, along with severe pain, the dog will puke blood. Although the healing process might be very challenging, proton pump inhibitor medication is usually an effective way to reduce stomach acid and, therefore, help reduce the severity and number of stomach ulcers.


Parvovirus is one of the deadliest and most contagious diseases in dogs. If a dog gets parvo, it will experience severe vomiting and diarrhea, which will lead to dehydration and loss of electrolytes. Unfortunately, there’s no effective antibiotic-like medication against parvovirus, so the condition is very hard to cure. However, intensive emergency treatment of parvovirus in the early stages of the disease will give your pet a chance to survive. Therefore, it’s crucial to take your dog in for an urgent vet visit.


Antifreeze is a sweet-smelling chemical often stored on the bottom shelves of kitchen cabinets. Since dogs are explorers by nature, they like looking for food in the kitchen. Unfortunately, accidental ingestion of only 3 ounces of antifreeze is enough to kill an average-sized dog.

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Intensive blood vomiting is one of the early symptoms of antifreeze poisoning. If you suspect that your pet may have drunk antifreeze, act quickly, as antifreeze is often deadly even with immediate treatment.


Blood in a dog’s vomit can also be caused by hookworms – parasites that chew holes in the intestines and eat the pet’s blood. When these worms attach themselves to the inner walls of the intestines, they inject a blood-thinning toxin to keep the blood flowing. Once there are a lot of parasites on the pet’s intestinal lining, your dog will start puking up blood.

Blood-clotting disorders

Blood-clotting disorders (coagulopathy) are often responsible for internal bleeding in dogs, which, in turn, causes them to throw up blood. This happens mostly to dogs who suffer from liver failure, cancer, or thrombocytopenia. Also, if your pet’s body cannot make blood clots, this may signal that it’s suffering from a genetic disorder such as hemophilia.

Some toxins and pesticides might also affect blood coagulation in dogs, making them prone to bleeding.


Among different types of cancer in dogs, stomach cancer is the most common cause of bloody vomit. Esophageal tumors can lead to bloody vomit as well. Usually, dogs diagnosed with cancer will also experience other symptoms such as abdominal pain, fever, weight loss, fatigue, and diarrhea. Older dogs are especially prone to cancer.

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Bilious Vomiting Syndrome

The term “bilious vomiting syndrome” is used to describe persistent vomiting in dogs. Canines suffering from inflammatory bowel disease or giardiasis are more likely to suffer from this syndrome.

If your puppy is vomiting a lot due to flu or virus, blood vessels in its stomach might break, leading to minor bleeding. If this is the case, you will notice specks of blood in the dog’s vomit.

Inflamed stomach

Chronic gastroenteritis is an illness during which a dog suffers from prolonged stomach inflammation. Conditions such as hyper-acidic syndromes, metabolic, auto-immune, or endocrine diseases might irritate the stomach lining. Long-term gastroenteritis usually occurs in older dogs and toy breeds such as Lhasa Apsos, Maltese, Shih-Tzus, and Miniature Poodles. The amount of blood in the vomit might increase as stomach inflammation becomes more severe.

Hemorrhagic gastroenteritis

Hemorrhagic gastroenteritis is a condition that causes sudden vomiting and diarrhea in otherwise healthy dogs. Pets diagnosed with the disease throw up blood mixed with mucus and bile. In small dogs, hemorrhagic gastroenteritis can quickly cause dehydration and, therefore, kidney failure. It’s suspected that changes in the pet’s diet can trigger this condition, and hyperactivity, stress, and anxiety might worsen the situation.

Bacterial infections

Bacterial infections caused by salmonella, campylobacter, clostridia, or E. coli can result in bloody vomiting in dogs. Another term for this condition is hemorrhagic gastroenteritis. Generally, younger dogs and pets with weakened immune systems are more vulnerable to infections. Other symptoms of hemorrhagic gastroenteritis include fever, upset stomach, diarrhea, fatigue, and loss of appetite.

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Hypovolemic shock is a lethal condition caused by a lack of blood flow in the body due to excessive bleeding. It is one of the most severe issues that can cause a dog to throw up blood. If bleeding is continuous, the dog may experience organ failure or pass out.

General health problems

Other diseases can also cause blood to seep into the intestinal tract and mix digested food. Thus, your dog might vomit blood every time it feels unwell.


Your veterinarian will likely use blood tests, urine, and fecal analysis to determine why your dog is vomiting up blood. Sometimes, it is also necessary to perform organ screening and X-rays to determine the cause of the issue.

Treatment for dogs throwing up blood

Treatment is always adjusted based on the underlying cause of hematemesis. The two main stages of a typical treatment plan are supportive care and therapy addressing the initial trigger. Generally, vets recommend using the following for supportive care:

  • Antacids
  • Anti-nausea medication
  • Stomach lining protectants
  • Fluid therapy for dehydration and electrolyte balance
  • Bland diet

All of this is aimed at slowing down bleeding and vomiting.

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Depending on the severity of the dog’s condition, the vet may prescribe oral medications and send the pet home or hospitalize it. If your pet is experiencing severe internal bleeding, ulcer perforation, or excessive vomiting, you will have to stay in the hospital with your dog, as emergency treatment for hemorrhage or shock may be needed. Sometimes, the vet may also need to perform blood transfusions or IV treatment to replace fluids that were lost due to excessive vomiting.

How Can I Prevent My Dog From Vomiting Blood?

Bloody vomiting caused by the ingestion of toxic substances can be avoided by keeping these products away from your pet. However, there are many causes of hematemesis which develop over time or are caused by genetic conditions and cannot be prevented.

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To minimize the chances of bloody vomit, remember to regularly vaccinate your dog and give it parasite prevention medicine. Do not allow the pet access to toxins, chemicals, poisonous plants and foods. Choose only a complete and well-balanced diet for your furry friend.

Remember that bloody vomit in dogs can lead to very serious problems very quickly, so consult your vet right away.


What would make a dog throw up blood?

There are multiple reasons for a dog to throw up blood. For instance, the pet may have cuts in its mouth, stomach, or intestines resulting from chewing on bones or swallowing foreign objects. Bloody vomit can also be caused by antifreeze poisoning, stomach cancer, parvovirus, stomach ulcers, and other conditions.

Why is my dog throwing up pink blood?

Pink blood in vomit is often a signal of bleeding in the stomach or upper small intestine.

What should I do if my dog vomits blood?

Immediately bring your dog to a vet since there could be severe underlying reasons for bloody vomiting, including cancer or parvovirus.