Most cat owners have experienced the unpleasant sensation of cat sick between the toes on a nighttime bathroom trip, or as a nice addition to your favourite rug. Vomiting is the active expulsion of stomach contents, which in cats can be violent, and may have many causes. It needs to be differentiated from regurgitation: where food is brought up with minimal effort from the oesophagus before ever reaching the stomach.

You may see warnings signs such as drooling, swallowing, licking their lips more, or hiding away. Short-term vomiting consisting of one or two episodes, or lasting less than 24 hours, in an otherwise healthy cat is usually nothing to worry about.

What do I do if my cat is sick?

If your cat is sick once or twice but appears otherwise well, remove their food for a few hours, then feed small amounts of a highly digestible food such as chicken, or a prescription diet from your vet. Allow them constant access to a small amount of water. After 24 hours go back to your usual routine.

When should I be worried?

It is best to contact your vet if your cat: 

  • continues to repeatedly vomit.
  • cannot keep water down
  • is lethargic or listless
  • has pale, dry, cold or yellow gums
  • has diarrhoea alongside the vomiting
  • could have eaten something unusual
  • has a known underlying condition such as diabetes or renal disease
  • has blood in the vomit.

What could be the reason for the vomiting?

 Occasional vomiting may be caused by:


Cats often ingest hair while grooming. If it forms into clumps it may irritate the stomach, eventually being vomited up. If your cat vomits hairballs frequently your vet may suggest treatments or diets to reduce hair build-up and grooming your cat regularly to reduce the volume of hair ingested.

Eating too rapidly

Cats that gobble food too quickly may regurgitate. If you’ve got multiple cats make sure you have separate feeding bowls in separate locations to reduce competition. Try serving dry food in a used egg carton, or putting kibble in plastic bottles with holes that dispense the food as it rolls. These puzzle feeders slow eating, create mental challenge, combat boredom and increase exercise which combats weight gain.

Eating too much at once

Cats naturally eat small amounts and often. While not always practical, specialists suggest 5 small meals a day. Dry kibble absorbs fluid in the stomach and swells which may cause vomiting, especially in older cats.

Eating spoilt food or hunting

Like us, they can be susceptible to the bacteria or spoiled food or something they’ve caught. This may result in irritation of the stomach.

More serious causes for vomiting

These are some of the more serious causes, where vomiting occurs on a more regular basis;

 Ingestion of foreign bodies

Cats are more particular about what they eat than dogs but we do occasionally see cats with blockages. Cotton or string can cause a blockage or trauma to the gut.

Ingestion of certain toxins

We see fewer toxicities in cats because of their fussy nature, with a few exceptions.

Some cats like to nibble on grass. If unavailable, or out of boredom, they may eat house plants such as Dieffenbachia (Dumb Cane) and lilies which are toxic. Ask your vet before bringing new plants into your house or garden.

Cats like the taste of antifreeze but it’s especially toxic to them. Never use it in ornamental water features, keep bottles secure and labelled, and wipe up spills immediately. Vomiting, increased thirst, lethargy and lack of appetite may be signs of ingestion. Ingestion is usually not witnessed, partly why it’s often fatal. Call your vet immediately if you suspect ingestion.

Food allergies or new foods

Not all foods suit all cats and any diet change should be slow, taking at least a week. It’s also thought some cats may actually be allergic to certain proteins in foods. If your vet suspects this, they may recommend a hypoallergenic diet using hydrolysed proteins. These are proteins that are broken down into very small pieces so are highly unlikely to cause an allergic reaction.

Parasites – roundworms, tapeworms and fleas

Roundworms are the most common intestinal parasite, affecting cats of all ages. Large burdens can be found in kittens resulting in vomiting, diarrhoea and a failure to thrive. Tapeworms are transmitted via hunting or by fleas, so older cats are more prone. There are many ineffective medications for sale so it’s best to speak to your vet before administering a product. Adult cats should be wormed every 1-3 months, and kittens more frequently.

Cats with kidney disease or liver disease

Other signs include lethargy, lack of appetite, weight loss and increased thirst. Cats with liver disease may have a yellow discolouration to the skin/gums. Liver disease can occur alongside intestine and pancreatic disease in a complex known as ‘triaditis’. If your vet suspects underlying medical reasons for vomiting, blood tests and other investigations may be advised. Treatments options will depend on the organs involved and severity of disease.

Gastrointestinal diseases

Infectious diseases caused by bacteria, viruses or small parasites known as protozoa can cause gastrointestinal signs. Inflammatory bowel diseases are a complex group of disorders caused by an immune reaction and result in persistent or intermittent diarrhoea, and/or vomiting. It may be part of the above mentioned ‘triaditis’ syndrome.


The two most common tumours affecting the stomach and intestines are lymphoma and adenocarcinoma. They may cause a partial blockage resulting in vomiting, weight loss, diarrhoea and appetite loss. The cat’s age, condition, the tumour location, the severity of disease and your wishes will affect treatment options. Surgery, chemotherapy or radiotherapy may be options once diagnosed. Sadly, sometimes euthanasia may have to be considered.

What will my vet do?

After taking a history and examining your cat your vet may advise dietary adjustments and medical treatments alone if the symptoms are mild. With more severe symptoms, investigations such as blood tests, x-rays, urine samples or ultrasound may be discussed. Treatment may include intravenous fluids, antiemetics (anti-vomiting drugs) and stomach protectants.

If a blockage is suspected then surgery may be discussed. The most appropriate treatment is the one that will address the underlying cause, whatever that may be, and your vet is perfectly placed to determine that and then to get your cat on the mend.

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