Vomiting of Blood in Dogs (Hematemesis)

PetMD Editorial
By PetMD Editorial
Published: August 20, 2008
Updated: April 28, 2022
Vet Reviewed by Lauren Jones, VMD

Hematemesis, or the vomiting of blood in dogs, can be caused by several medical and non-medical conditions. Some of the more common causes include: 

  • Disruption in the lining of the esophagus
  • Irritation of the stomach or intestines
  • Inflammation in stomach or intestines
  • Injury in the mouth or lungs

Hematemesis is relatively common in dogs, and can affect a wide range of systems depending on the source. The gastrointestinal system may be affected due to trauma, ulcer, cancer, inflammation or the presence of a foreign object. All of these may lead to a dog vomiting blood.

Symptoms and Types

Vomiting blood in dogs is a symptom of a variety of problems and diseases. Blood in vomit may appear as fresh blood, formed clots or digested blood resembling coffee grounds. 

Associated symptoms include lack of appetite (anorexia), abdominal pain and blackish, tar-like feces (melena).

Loss of blood through vomit may lead to a low red blood cell count (anemia), in which case additional symptoms can include heart murmur, weakness to the point of collapse, and a rapid heartbeat.


A wide variety of causes may be responsible for hematemesis. Gastrointestinal diseases, such as inflamed bowels from inflammatory bowel disease (IBD), or ulcers, can both be causes for hematemesis.

Various metabolic, neurological, respiratory and viral infections may be responsible for incidents of hematemesis. Ingestion of toxins, including household cleaners, are a common cause of hematemesis in dogs.

Coagulopathy, or lack of proper blood clotting, may result from liver failure, or a reduced blood platelet count (thrombocytopenia) due to toxin or drug exposure.

Hematemesis may also follow a traumatic incident, such as being hit by car; severe burns; heatstroke; major surgery; exposure to poisons from heavy metals, such as iron or lead; and snake bites. Exposure to toxic plants and pesticides may also cause vomiting of blood in dogs. Ingestion of rat poison is a cause of improper blood clotting.

Critically ill animals are at a higher risk for hematemesis. Other factors that can increase the risk of hematemesis are certain drugs, such as NSAIDs, or nonsteroidal anti-inflammatories; shock; or diseases that cause thrombocytopenia—a reduced blood platelet count.


Tests for diagnosis include blood tests, and urine and fecal analysis. Imaging tests such as ultrasound and X-ray may also be used to pinpoint inner disturbances. The diagnosis for hematemesis may range from any number of the aforementioned causes, from contact with toxic substances to cancer.


Treatment varies greatly depending on the cause of hematemesis. Any underlying cause must be treated upon diagnosis. After the cause is identified and addressed, if vomiting is no longer excessive, recovery may continue at home.

For severe internal bleeding, ulcer perforation or excessive vomiting, inpatient care may require emergency treatment for hemorrhage or shock, or there may be the need for blood transfusions or IV treatment to replace fluids lost from excessive vomiting.

Your veterinarian will send home several types of oral prescription pet medications for your dog to continue at home. These may include dog medications to reduce nausea, heal stomach ulcers, reduce stomach acid, and improve appetite.

Living and Management

A delicate diet of highly digestible foods is recommended after incidents of hematemesis. Dog food should be low in dietary fat and low in fiber so that the digestive system is not stressed. Your veterinarian will recommend what is best for your specific pet, but boiled chicken and white rice is a common home-cooked option while your dog heals.

Further care is dependent upon the cause and consequent treatment given for hematemesis.


Hematemesis due to the ingestion of toxic substances can be avoided by ensuring that animals do not have access to poisonous plants, foods and chemicals. Vomiting of blood in dogs can become a very serious health concern very quickly—call your veterinarian immediately.


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