Seeing blood in your old dog’s vomit is one of the most frightening things you can experience.
Vomiting blood in an older dog is a symptom that should never be ignored. Even a small amount of blood can be a sign of a serious problem, and senior dogs are less able to cope with blood loss and stress.
Old Dog Throwing Up Blood: Why It Happens
An old dog throwing up blood usually happens because of irritation, injury, or disease affecting the stomach, intestines, or internal organs.
Common causes include stomach ulcers, gastrointestinal bleeding, ingestion of harmful substances, liver or kidney disease, tumors, severe infections, and clotting disorders.
As dogs age, their organs become more fragile and less able to recover from inflammation or injury, making bleeding more likely. Medications, chronic illness, and weakened immunity can also contribute.
In many cases, vomiting blood is a warning sign that immediate medical evaluation is needed.
Old Dog Throwing Up Blood: Common Causes
Stomach Ulcers and Erosions
Stomach ulcers are one of the most common causes of blood in vomit in older dogs. These occur when the protective lining of the stomach becomes damaged, allowing acid to irritate and erode the tissue.
Ulcers often develop after long-term use of pain medications, especially non-steroidal anti-inflammatory drugs, which are commonly prescribed for arthritis.
Stress, severe illness, and infections can also weaken the stomach lining.
Dogs with ulcers may vomit blood that looks bright red or dark like coffee grounds. They may also lose their appetite, seem weak, drool excessively, or appear uncomfortable after eating. Left untreated, ulcers can worsen and lead to dangerous internal bleeding.
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Gastrointestinal Tumors or Cancer
Cancer becomes more common as dogs age, and tumors in the stomach or intestines can cause bleeding that shows up in vomit.
These growths may slowly damage surrounding tissue, leading to chronic irritation and blood loss. Some tumors are benign, while others are aggressive and spread quickly.
In addition to vomiting blood, dogs with gastrointestinal cancer may lose weight, eat less, develop diarrhea, or appear tired and withdrawn. Blood loss may also cause pale gums and weakness. Early diagnosis improves treatment options and comfort.
Liver or Kidney Disease
Chronic liver and kidney disease can interfere with normal blood clotting and toxin removal. When these organs fail, harmful substances build up in the bloodstream and damage the digestive tract.
Liver disease may prevent proper production of clotting proteins, making even small stomach injuries bleed easily. Kidney failure allows toxins to irritate the stomach lining, leading to ulcers and bleeding.
Signs often include increased thirst, frequent urination, appetite loss, vomiting, bad breath, weight loss, and dull coat quality. Vomiting blood in these cases usually signals advanced disease.
Ingestion of Toxins or Foreign Objects
Older dogs may accidentally swallow toxic substances, spoiled food, sharp objects, or household chemicals. These materials can severely damage the stomach and intestines.
Toxins such as rat poison, certain plants, human medications, and cleaning products may cause internal bleeding. Sharp objects like bones, toys, or sticks can tear delicate tissue.
Symptoms may include sudden vomiting, drooling, abdominal pain, diarrhea, lethargy, and blood in vomit or stool. This situation is always an emergency and requires immediate veterinary care.
Read more: Old Dog Not Eating and Vomiting (Why appetite loss matters)
Severe Infections and Hemorrhagic Gastroenteritis
Bacterial, viral, or parasitic infections can inflame the digestive system and damage blood vessels in the stomach and intestines.
Hemorrhagic gastroenteritis is a condition that causes sudden, severe vomiting and bloody diarrhea. It can lead to dehydration and shock within hours.
Dogs with severe infections may appear weak, feverish, depressed, and unwilling to eat. Vomiting blood in these cases reflects significant inflammation and fluid loss and should be treated urgently.
Blood Clotting Disorders
Some older dogs develop problems with normal blood clotting due to genetic conditions, immune disorders, liver disease, or medication reactions.
When clotting is impaired, even minor irritation in the stomach can cause ongoing bleeding. Internal bleeding may also occur in other organs.
Signs include unexplained bruising, nosebleeds, bleeding gums, weakness, pale gums, and blood in vomit or stool. These conditions can become life-threatening without treatment.
Related: Old dog throwing up (Causes and treatment)
Old Dog Throwing Up Blood: Complications
Vomiting blood in an older dog can lead to serious and life-threatening complications if not treated immediately.
Ongoing bleeding may cause anemia, resulting in weakness, pale gums, rapid breathing, and collapse.
Blood loss and vomiting together can quickly lead to severe dehydration and shock, placing strain on the heart and other organs.
Underlying causes such as stomach ulcers, internal bleeding, poisoning, kidney failure, or cancer may rapidly worsen without intervention.
There is also a risk of aspiration pneumonia if blood or vomit is inhaled. Because senior dogs have reduced ability to compensate, throwing up blood is always a medical emergency requiring urgent veterinary care.
When to Call or Visit Your Veterinarian
Call or visit your veterinarian immediately if your dog vomits any amount of blood, even once.
Seek emergency care if vomiting continues, becomes darker, or is accompanied by diarrhea, collapse, or weakness.
Urgent evaluation is needed if your dog refuses food and water, seems confused, has pale or yellow gums, or shows signs of pain.
Immediate treatment is critical if your dog has a history of liver disease, kidney disease, cancer, or is taking long-term medications.
If your dog may have ingested toxins, sharp objects, or unknown substances, go to an emergency clinic without delay.
Related: Old dog throwing up yellow bile (What it means)
Key Takeaway
An old dog throwing up blood is always a serious warning sign that something is wrong internally. It may be caused by ulcers, organ disease, cancer, toxins, infections, or clotting problems, all of which require professional care.
Prompt veterinary evaluation gives your dog the best chance for recovery and comfort. If you notice blood in vomit, trust your instincts and seek help quickly.
Early treatment can prevent complications, reduce pain, and improve your dog’s quality of life during their senior years.