Why Is My Cat Vomiting? Causes and When to See a Vet

Most cats vomit now and then. A hairball once in a while is normal, but frequent vomiting is not, and it can be the first sign of a serious illness. Here's how to tell the two apart and when to call a vet.

Vomiting or regurgitation?

The two look similar but point to different problems, so tell your vet which one you saw.

Vomiting is active. The cat drools, licks its lips or retches, and its belly contracts. What comes up is partly digested food, often with foam or yellow or green bile.

Regurgitation is passive. Food comes up with no warning or effort, usually soon after eating. It's often undigested and tube-shaped, with no bile. It usually points to a problem in the oesophagus.

How often is too often?

A cat that brings up a hairball once every week or two, and is otherwise well, is usually fine. See a vet promptly if your cat:

• Vomits more than once a week
• Seems tired or weak, or has a poor appetite
• Has blood in the vomit
• Drinks or urinates more or less than usual
• Has diarrhoea as well

Common causes

Hairballs. The most familiar cause. Cats swallow loose hair when they groom, and it collects in the stomach. Brushing your cat often, especially a long-haired one, reduces it, and regular grooming keeps the coat in good order. A cat that retches again and again without bringing anything up needs to be seen.

Diet. Eating too fast, a sudden change of food, rotten food, plants, string or table scraps can all cause vomiting. Change food gradually over 7 to 10 days. A slow-feeder bowl or puzzle feeder can help a cat that gulps its food.

Food intolerance or allergy. This can cause long-term vomiting and diarrhoea, and sometimes itchy skin. The vet may suggest a diet trial lasting several weeks.

Inflammatory bowel disease (IBD). Long-lasting inflammation of the gut that causes vomiting, diarrhoea and weight loss. It's common in cats and is usually managed with diet, and sometimes medicine.

Kidney disease. Common in older cats. Look for more drinking and urinating, weight loss, poor appetite and bad breath. Blood and urine tests find it.

Hyperthyroidism. An overactive thyroid in middle-aged and older cats. A big appetite with weight loss, restlessness, vomiting and diarrhoea are typical. A blood test shows it, and it can be treated.

Pancreatitis. Inflammation of the pancreas. The cat may vomit, stop eating, seem sore in the belly and be very tired.

Foreign objects and blockages. Kittens and young cats swallow string, hair ties, rubber bands, tinsel and small toys. Signs include repeated vomiting, no appetite, belly pain and straining. If you see string coming from the mouth or bottom, don't pull it. See a vet at once. A blockage is an emergency and often needs surgery.

Poisons. Lilies are extremely dangerous to cats, and so are antifreeze (ethylene glycol), human painkillers such as paracetamol and ibuprofen, some cleaning products and rat poison. If you think your cat has eaten something toxic, take the packaging or plant with you and go to a vet immediately.

Worms and other parasites. These often cause vomiting and diarrhoea in kittens. A stool test and deworming treat them.

Cancer. Lymphoma and adenocarcinoma are the common types in the digestive system. Signs include long-term vomiting, weight loss and a poor appetite.

Other causes include constipation, diabetes and liver disease, which is why a vet check matters.

When to see a vet

Go the same day if your cat:

• Vomits repeatedly or can't keep anything down
• Has blood in the vomit, red or like coffee grounds
• Is in pain, hiding, hunched or crying
• Is very tired or weak
• Hasn't eaten for 24 hours
• Has a swollen or painful belly
• Has pale or yellow gums
• Has trouble breathing, seizures or collapse
• Has eaten a toxin or a foreign object

If this happens outside opening hours, go to an emergency vet clinic. We're open Monday, Thursday and Friday 10:00 to 16:00, and Tuesday and Wednesday 09:00 to 17:00 and can see your cat during those hours. Book our veterinary service or contact the clinic.

Book an appointment for vomiting more than once a week, weight loss, changes in appetite or thirst, behaviour changes or a poor coat.

What the vet does

The vet asks how long the vomiting has gone on, what it looks like, what your cat eats and whether it could have got into something. They check hydration, feel the belly and look at the mouth. Common first tests are blood tests, a urine test and a stool test, with a thyroid test for older cats. If these don't explain it, the vet may suggest X-rays, an ultrasound scan, or a biopsy.

Treatment

It depends on the cause. In general:

• Fluids by drip or under the skin for dehydration.
• Anti-nausea medicine, such as maropitant, and medicine to reduce stomach acid.
• A bland, easy-to-digest diet once the vomiting has stopped.
• Specific treatment for the cause: deworming, medicine for thyroid disease, diet and anti-inflammatory medicine for IBD, a special diet and fluids for kidney disease, or surgery for a blockage or a tumour.

Don't stop your cat eating at home unless your vet tells you to. Cats that go without food for a day or more can develop a serious liver problem. Call your vet if your cat hasn't eaten for 24 hours.

At home

• Feed at regular times, in small meals.
• Switch foods slowly.
• Brush your cat often to cut down on hairballs.
• Keep lilies, human medicines, cleaning products, string and small objects out of reach.
• Keep stress low with a steady routine, hiding places and enough litter trays (one per cat plus one).
• Take older cats and cats with long-term illness for regular check-ups.

The outlook depends on the cause. Hairballs, diet problems and worms usually clear up easily. Hyperthyroidism and early kidney disease can be controlled. Advanced kidney disease and some cancers are harder to treat, which is another reason to see a vet early.