Vomiting and Diarrhea (Gastritis) in Cats


Vomiting and diarrhea are medically known as gastroenteritis, or gastro, which is the inflammation or infection of the small intestine and stomach. There are several causes of gastroenteritis including:

The occasional bout of vomiting or diarrhea is quite common in cats, vomiting especially. Prolonged vomiting and diarrhea, which lasts longer than 24 hours should be checked out by a veterinarian. Dehydration can quickly occur, which is life-threatening.


Vomiting and diarrhea (which may or may not contain blood, mucus or be frothy in appearance), are the most common symptoms. You may also notice:


Your veterinarian will perform a physical examination of your cat and obtain a medical history from you. He will want to know how long your cat has had vomiting and diarrhea if you have noticed any other symptoms, what food he has been eating if he is on any medication.

Diagnostic workup:

  • Fecal flotation: A stool sample is mixed with a liquid solution and parasitic eggs or cysts float to the top. Your veterinarian can then check under the microscope to determine the parasite.
  • Complete blood count: A blood test that measures the cellular components of the blood (red blood cells, white blood cells and platelets. May reveal signs of inflammation.
  • Biochemical profile: Performed on the clear/fluid portion of the blood, the biochemical profile measures a number of chemicals and enzymes which provides important information on the status of the kidneys, liver and electrolytes.
  • Urinalysis: To check for kidney disease, infection, check for dehydration or sugar in the urine (which is indicative of feline diabetes).
  • T4 concentration in cats over 5 or 6 years of age to check for hyperthyroidism.
  • X-rays and/or ultrasound to check for obstruction, foreign bodies or tumours.
  • Endoscopy of the intestines to obtain biopsies.


Fluids to treat dehydration which is common in cats who have vomiting and diarrhea.

Fasting for up to 24 hours to rest the stomach and speed up recovery. Your cat will be fed a bland diet for a few days after this.

Other treatments are aimed at addressing the underlying cause and may include:

  • Anti-parasitic medications to treat parasites.
  • Antibiotics to treat bacterial infections.
  • Radioactive iodine or surgical removal of the thyroid gland if your cat has hyperthyroidism.
  • Viral infections usually have to run their course with supportive care provided while your cat fights the infection.
  • Gastric decontamination to treat a cat who has ingested poison, as well as supportive care which may include fluids, nutrition and where available, an antidote.
  • Changing your cat’s diet or avoiding foods that cause intolerances (such as milk).
  • Surgery to remove gastrointestinal obstructions.
  • Hairballs may be treated with a change in diet or the addition of lubricants of fibre to the diet. Read here for more detailed instructions on how to treat hairballs at home.
  • Painkillers and anti-nausea medications to treat pancreatitis along with supportive care and if possible, treating the underlying cause.


  • Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio