Reasons for a Cat to Vomit Blood

Updated April 07, 2017

Discovering blood in your cat's vomit can be an alarming moment for any pet owner. Vomiting blood, called hematemesis, is a symptom which requires immediate attention, since it can be a sign of serious ailments. If you discover fresh, red blood or old, brown blood in your cat's vomit, you will need to contact your vet.

Clotting Disorders

Abnormalities in blood clotting, called coagulopathies, can cause excess bleeding in a cat. This can cause blood to appear in the cat's vomit, mucous membranes, skin and urine. These are potentially life threatening disorders and require a veterinarian's attention as soon as they are discovered. Coagulapathies can be genetic or caused by outside factors, such as medication or poisons. Cats who have eaten rodents treated with pesticides may develop a vitamin K deficiency, which in turn causes bleeding.

Stomach Ulcers

A stomach ulcer in a cat is caused by damage to the stomach caused by digestive enzymes or stomach acid. This can result in blood in the stomach, which is then vomited.

Ulcers have many causes. Ingesting a foreign object, stress, caustic substances and even parasites can cause the stomach to produce excess acids. They can be treated by drugs and lifestyle changes, such as removing the causes of stress and better meal regulation.


Discovering that your cat has a tumour can be frightening, but many tumours are both benign and treatable. When a tumour forms in the stomach or intestines, this can cause either fresh or digested blood to appear in vomit. Tumours can be serious and need to be diagnosed and treated by a professional. Benign tumours can be surgically removed while more serious tumours may require additional therapy with drugs.


Parasites such as roundworms, hookworms and tapeworms can cause bloody vomit in cats. These infestations can be prevented by regular worming treatments. You may be able to diagnose a problem at home by examining your pets' stools for egg sacs or worms. Once an infestation is diagnosed, prescription medication should be able to treat the parasites and stop the blood in your cat's vomit.

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About the Author

Gwen Wark is a freelance writer working from London, Dublin, and New York. She has been a published writer since 1998 with works appearing in both university and local publications. Her current writing projects include SEO, web copy, print and advertising features. She holds a Bachelor of Arts in English with a minor in history from Rutgers University.