Vomiting of blood, called hematemesis, is a fairly common symptom in dogs that can be associated with a number of different diseases. Vomited blood is easily recognizable when it is fresh, but if it is partially digested it often has a dark grainy appearance, similar to old coffee grounds. Any problem that erodes the lining of the stomach can expose blood vessels and cause gastrointestinal hemorrhage that will make your dog vomit blood. Ulcers, gastritis or drugs like NSAID’s are common reasons. Tumors located in the stomach or esophagus can also cause this problem, as well as infections like Coronavirus and Parvovirus. Less obvious causes include liver or kidney disease, toxin ingestion, shock, internal trauma that bleeds into the stomach, and diseases that affect blood coagulation. Hematemesis should be distinguished from coughing of blood (hemoptysis), which is due to a respiratory problem, although occasionally dogs may swallow blood from a respiratory tract disorder and vomit it up in a similar way to hematemesis. Sometimes sores on the mouth or dental problems with bleeding are also mistaken if the source of the blood is not obvious. Hematemesis is a nonspecific symptom, but it can be a sign of serious disease.

Dogs may vomit blood for a variety of reasons. Veterinarians call this hematemesis. Depending on the amount of blood that is present, it can be associated with mild problems like stomach upset, or with serious life-threatening conditions.

Take your dog to see a veterinarian if you notice any of the following symptoms. Vomiting of large amounts of blood should be treated as an emergency.

Hematemesis may be either acute or chronic.

There are numerous different conditions that could cause your dog to vomit blood. These are some of the most likely:

Hematemesis is not a diagnosis in itself, but is an important symptom that will help the veterinarian identify your dog’s condition. You will need to give a complete medical history; the recent ingestion of medications like NSAID’s or corticosteroids can be especially important. Recent vaccination, exposure to poisoning, or potential trauma that could cause internal bleeding or shock are also relevant. A good description of your dog’s symptoms, including how much blood is present and whether the problem is acute or chronic, will help to eliminate some possibilities. Other symptoms like fever, diarrhea, or signs of shock can indicate what might be wrong with your dog.

Depending on the severity of the condition, blood tests will usually be taken to check for anemia, clotting disorders, or high levels of white blood cells from infection. This can also help to diagnose liver and kidney disease as well as paraneoplastic syndromes from cancer. Urine analysis can further evaluate many of these conditions. Ultrasound or x-rays may be necessary to check for cancerous tumors or internal injuries.

Dogs that are very ill and have lost a lot of blood may need immediate blood or plasma transfusions. Intravenous fluids and electrolytes will treat shock and balance dehydration from vomiting. Severe forms of gastritis, especially hemorrhagic gastroenteritis, can be life-threatening if they are not treated immediately. Viral infections like Parvovirus and Coronavirus will need to be managed symptomatically in this fashion also. Antibiotics may be given to treat vomiting caused by bacterial infection.

If the problem is related to chronic gastritis or ulcers, the veterinarian will treat your dog with antacids and antiemetics. Further treatments may then focus on eliminating the source of these diseases. Dogs may need to be treated for an autoimmune problem or follow a strict diet to avoid allergens. Activated charcoal may be given for drug overdoses or poisoning. Other medications may focus on eliminating parasites as well as treating liver or kidney disease. NSAID’s will be discontinued. Dogs with cancerous tumors, foreign objects, or internal injury may need surgery. In the case of an injury such as a gut laceration, emergency surgery could be required. For cancer, chemotherapy may be recommended post-surgery, or in the case of inoperable tumors.

The veterinarian will evaluate your dog’s chance of recovery upon diagnosis. Many conditions, especially those with only a small amount of blood can be treated easily and your dog will make a full recovery. Some conditions, like cancer, or liver and kidney disease, may require long-term management. Others can be immediately life threatening. Effective treatment will depend on the severity of your dog’s condition and the promptness of medical treatment.