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Vomiting pure blood (hematemesis) in Dogs

Author: Dr. med. vet. Gisa Löwe | Last modified: 17.02.2026

When to visit the vet?

Urgent see a veterinarian within 24 hours

Escalation: RED if there are large amounts of blood, repeated hematemesis, pallor/weakness, collapse, tarry stool (melena), severe abdominal pain, suspected ulcer/perforation, foreign body, or clotting disorder.

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Definition

HematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. in dogs is vomiting pure blood. This symptom may indicate serious internal bleeding or a disease of the digestive system and requires immediate veterinary attention.

Can Occur with the Following Diseases:

Basics and possible causes

Vomiting blood in dogs can be caused by various factors. The most common causes include injuries or irritation of the digestive tract, which can be caused by foreign bodies, ulcers, or tumors. Systemic diseases that impair blood coagulationBlood coagulation is a process that helps stop Bleeding when a blood vessel is damaged. Platelets and certain proteins in the plasma form a blood clot that seals the wound. can also lead to hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention..

A common cause of bloody vomiting is inflammation of the stomach or intestinalIntestinal refers to the intestine, the part of the digestive tract that extends from the stomach to the anus. Intestinal diseases affect the small and/or large intestine. lining, which can be caused by medications such as non-steroidalNon-steroidal refers to medications or substances that are not steroids and often have anti-inflammatory, analgesic, or antipyretic effects. They are used in dogs and cats to treat Pain and Inflammatory conditions. anti-inflammatory drugsAnti-inflammatory drugs are medications that reduce inflammation. They can be divided into nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids and are used in dogs and cats to reduce Inflammatory conditions and Pain. or by infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. These inflammatory conditions can damage the lining and cause bleeding.

Poisonings, for example from rat poison or certain plants, can also lead to internal bleeding that shows up as hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention.. In some cases, traumaA trauma refers to a physical injury or damage caused by external force. Traumas can range from simple cuts to severe multiple injuries. such as a blow to the abdomenThe abdomen, also known as the abdominal cavity, is the part of the body located between the rib cage and the pelvis. It houses several important organs, including the stomach, liver, kidneys, intestines, and spleen. can also cause GI tract bleeding.

Another possible factor is liver disease, in which the liver is unable to support blood coagulationBlood coagulation is a process that helps stop Bleeding when a blood vessel is damaged. Platelets and certain proteins in the plasma form a blood clot that seals the wound. effectively, which can lead to bleeding. Pancreatic diseases, such as pancreatitis, can also lead to bloody vomiting.

Small dogs and puppies are particularly susceptible to infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. by parasites, which can also damage the digestive system and cause bleeding. ParasiticParasitic refers to diseases or conditions caused by parasites. Parasitic infections can affect the digestive tract, skin, and other organ systems. infections can also affect the dog’s overall health and lead to further complications.

Typical accompanying symptoms

Pale gums: This may indicate blood loss and should be taken seriously. If the dog’s mucous membranes appear pale, this is a sign that the dog may be bleeding internally.
Weakness or lethargy: These symptoms often occur due to blood loss or anemia, which can be caused by internal bleeding. The dog may be less active or have difficulty getting up.
Loss of appetite: A dog that is vomiting blood may also refuse to eat, which can lead to further weakening and dehydrationDehydration occurs when the body loses more fluid than it takes in. This can lead to a number of problems, including headaches, Dizziness, and in extreme cases, renal failure or Cardiovascular collapse..
Increased thirst: Some dogs show increased thirst, especially if they have lost fluid or are dehydrated.
Pain or discomfort in the abdominalThe term "abdominal" refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. area: The dog may avoid its abdomenThe abdomen, also known as the abdominal cavity, is the part of the body located between the rib cage and the pelvis. It houses several important organs, including the stomach, liver, kidneys, intestines, and spleen. or react sensitively to touch, indicating pain or discomfort.
Dark, tar-like stool: This may indicate bleeding in the upper digestive tract. The stool is dark because the blood has been digested.
Increased heart or breathing rate: These symptoms can indicate shock or stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. due to blood loss and require immediate veterinary care.

When to see a vet?

It is crucial to see a veterinarian as soon as you notice your dog vomiting blood. HematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. can be a sign of a serious condition that requires immediate medical intervention. Delays in treatment can lead to serious complications, including shock, anemia, or even death.

The situation is particularly alarming when vomiting blood is accompanied by other symptoms such as weakness, pale gums, or confusion. These signs indicate significant bleeding or a systemic disease that must be treated immediately.

Even if the dog vomits blood only once and then appears normal, it is important to have a veterinary examination. Some causes of hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. can be intermittentIntermittent refers to something that occurs at intervals or starts and stops temporarily, such as intermittent Pain that comes and goes. and still require medical attention.

If you suspect your dog has ingested a toxicToxic means "poisonous" and refers to substances that can have harmful effects on the body, including damage to organs, cells, or disruption of metabolic processes. substance that is causing bloody vomiting, contact a veterinarian immediately or go to an emergency veterinary clinic. Prompt treatment can be crucial to minimizing the effects of the poisoning.

Symptom recognition for the pet owner and veterinary diagnostic procedure

Identifying hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. initially depends on the pet owner’s observation. It is important to note the color and consistency of the vomit, as this can provide valuable clues about the cause of the bleeding. Fresh, red blood usually indicates bleeding in the upper digestive tract, while darker, coffee-colored vomit suggests digested blood from the lower digestive tract.

The veterinarian will take a comprehensive medical history to narrow down possible causes. This includes questions about diet, medication intake, possible traumas, and the dog’s overall health status. A physical examination will be performed, including checking the mucous membranes for pallor and the abdomenThe abdomen, also known as the abdominal cavity, is the part of the body located between the rib cage and the pelvis. It houses several important organs, including the stomach, liver, kidneys, intestines, and spleen. for tenderness.

For further diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients., blood tests may be necessary to detect signs of anemia or infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. Imaging such as X-rayX-ray is an imaging technique that uses X-rays to create images of the inside of the body. It is often used to diagnose bone fractures, lung diseases, and other conditions. or ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. can help identify foreign bodies or tumors in the GI tract. In some cases, an endoscopyEndoscopy is a diagnostic procedure that uses an endoscope (a thin, flexible tube with a light source and a camera at the end) to examine and visualize the inside of the body, often for diagnostic or therapeutic purposes. may be required to directly view the digestive tract lining and take samples for a biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions..

Depending on suspicion, specific tests for infectiousInfectious describes the ability of a pathogen to be transmitted from one individual to another and trigger an infection. It also refers to diseases caused by such pathogens. diseases or parasites may also be performed. These tests are especially important in young dogs or dogs with access to infested environments.

What the pet owner can do and professional therapy options

Until the veterinary examination, try to provide your dog with a calm environment and withhold food to reduce strain on the digestive tract. Water should be available in small amounts to prevent dehydrationDehydration occurs when the body loses more fluid than it takes in. This can lead to a number of problems, including headaches, Dizziness, and in extreme cases, renal failure or Cardiovascular collapse., but only if the dog does not vomit again immediately.

Avoid giving your dog any medication without veterinary instructions, as some medications can worsen the problem or increase bleeding. In particular, do not give human medications, as these are often unsuitable for dogs.

Monitor the dog closely and note any symptoms that occur, as well as the frequency and amount of vomit. This information is valuable for the veterinarian in making an accurate diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients..

If the dog shows signs of shock, such as shallow breathing, trembling, or unconsciousness, take them to an emergency clinic immediately. Carefully place them in a carrier or on a blanket to stabilize them, and avoid unnecessary movement that could worsen the condition.

After veterinary treatment, it is important to follow the veterinarian’s instructions carefully, especially regarding diet and medication, to support recovery and minimize the risk of recurrence.

Outlook on current research

Hematemesis in dogs—vomiting pure blood—is a serious symptom that can indicate various underlying problems. Current research focuses on identifying molecular and genetic markers associated with this symptomatologySymptomatology refers to the entirety of symptoms associated with a particular disease or condition. It describes how a disease manifests itself externally.. The goal is to develop faster and more accurate diagnostic methods. These markers could help detect underlying causes such as stomach ulcers or tumors at an early stage, enabling more targeted treatment.

An interesting development in research is the use of non-invasive imaging techniques. Researchers are studying the use of advanced ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. and endoscopyEndoscopy is a diagnostic procedure that uses an endoscope (a thin, flexible tube with a light source and a camera at the end) to examine and visualize the inside of the body, often for diagnostic or therapeutic purposes. techniques to visualize the GI tract lining in dogs in greater detail. In the future, these methods could reduce the need for invasiveInvasive describes medical procedures or pathogens that enter the body or penetrate tissue. In medicine, invasive procedures can range from minimally invasive techniques to open surgery. procedures and make it easier to diagnose bleeding sites.

Another area of research is the development of new therapeutic approaches designed to promote the healing of stomach and intestinalIntestinal refers to the intestine, the part of the digestive tract that extends from the stomach to the anus. Intestinal diseases affect the small and/or large intestine. ulcers. These include studying natural remedies and probiotics that could protect the lining and support healing. Studies on the effectiveness of pre- and probiotics in the diets of dogs with gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. problems show promising results.

In addition, efforts are underway to better understand the role of stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. and diet in the development of gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. bleeding. Some studies suggest that certain diets and lifestyle habits could increase the risk of hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention.. Researchers are working to develop specific dietary guidelines that can minimize the occurrence of GI tract bleeding.

In preventive medicine, the role of vaccinations and regular health checks is also being studied to promote dogs’ overall health and improve early detection of potentially dangerous conditions that could lead to hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention.. Research aims to develop comprehensive preventive programs that can sustainably improve the health of pet dogs.

In summary, research is advancing on many levels to better understand and effectively combat hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. in dogs. Advances in genetic research, non-invasive diagnostics, therapeutic approaches, and preventive medicine promise to significantly improve the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment of this symptomatologySymptomatology refers to the entirety of symptoms associated with a particular disease or condition. It describes how a disease manifests itself externally. in the near future.

Frequently asked questions

What is hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. in dogs? HematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. is vomiting blood. In dogs, it can be fresh, red blood or dark, coffee-ground-like material indicating digested blood.
What are the most common causes of hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. in dogs? Common causes include gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. ulcers, tumors, poisonings, certain medications, and severe infections. Foreign bodies that injure the GI tract can also cause hematemesis.
How is hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. diagnosed in dogs? DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. begins with a thorough medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. and clinical examination. Additional diagnostic tests may include blood tests, X-rays, ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow., or endoscopy to determine the cause of the bleeding.
What treatments are available? The treatment depends on the cause. This may include medications to reduce stomach acid, antibiotics, surgery, or removal of foreign bodies. SupportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. care and a special diet may also be required.
Can hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. in dogs go away on its own? HematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. is rarely a problem that goes away on its own. It usually requires veterinary treatment to address the underlying cause and prevent further complications.
How can I help my dog at home? Until veterinary treatment, your dog should not have access to food to protect the stomach. Water should be offered in small amounts. Watch for changes and see a veterinarian as quickly as possible.
Is hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. in dogs life-threatening? Yes, hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. can be life-threatening, especially if there is major blood loss or the underlying cause is severe. Rapid veterinary intervention is crucial.
How can I prevent hematemesisHematemesis is the Vomiting of blood, indicating Bleeding in the upper gastrointestinal tract. In dogs and cats, this can be caused by ulcers, foreign bodies, poisoning, or Tumors and requires immediate veterinary attention. in my dog? Regular veterinary check-ups, a balanced diet, and avoiding potentially harmful substances can help reduce the risk. Also make sure your dog does not swallow foreign objects.
What role does diet play in preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring.? A balanced diet that is rich in fiber and low in harmful additives can help promote the health of the GI tract and reduce the risk of ulcers and other problems.
When should I see a veterinarian? If your dog is vomiting blood, you should see a veterinarian immediately. Even if it is a small amount, it can be a sign of a serious problem that requires professional diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment.