VetVits August 10, 2016

Cats, like most other species, will vomit from time to time. However, how do you know when they’re vomiting too much and whether there’s a real problem with their health?

Generally speaking, veterinarians feel that if a cat vomits occasionally, even up to one or two times per month, it can be considered relatively normal. They might very well have eaten something that has upset their gastrointestinal tract or picked up a transient illness. Some cats vomit just because what they’ve eaten doesn’t agree with them. However, more frequent vomiting is definitely a cause for concern, especially if it is accompanied by weight loss. So, what could cause this?

What are the causes of vomiting in cats?

Cats often throw up balls of excess hair. In the past, this was thought to be normal, particularly in long-haired cats. However, this behaviour is now considered to be associated with an underlying health issue. It may be that your cat is swallowing more hair, such as when they lick itchy skin, or that there is a problem with their ability to move the hair along the intestinal tract (1). Frequent vomiting of hairballs should therefore also warrant a trip to the veterinarian.

It’s important for cat owners to know the difference between vomiting and regurgitation. Vomiting is an active process with retching and abdominal heaving. Regurgitation, on the other hand, is more passive and seems almost as if it takes the cat by surprise: there are no forceful abdominal contractions associated with it. Vomiting and regurgitation can have different causes so it’s important that they can be differentiated.

Acute vs. chronic vomiting

Vomiting can be either acute, with a sudden onset, or chronic. Common causes of acute vomiting include a foreign body obstruction or eating something unsavoury, such as a dead bird. Affected cats may show no other symptoms or they may have lethargy and pain in the abdomen, but over time they can become dehydrated and very unwell. Chronic vomiting, however, can have a number of causes and these can be further divided into gastrointestinal or non-gastrointestinal.


Gastrointestinal diseases that are characterised by chronic vomiting include intestinal worms, food allergies, inflammatory bowel disease and cancer. With these conditions, the vomiting can be accompanied by weight loss or diarrhoea. One study found that 99 out of 100 cats with ongoing vomiting had chronic small intestinal disease, of which most cases were either enteritis or intestinal cancer (2). It’s not easy to tell these conditions apart, meaning that a biopsy of the intestinal wall is essential to avoid a wrong diagnosis (3).


Sometimes abnormalities outside of the gastrointestinal tract can also result in vomiting. Liver disease and kidney disease are both characterised by vomiting, but affected cats will also often drink excessive amounts of water and may lose their appetite. These conditions can occur without any identifiable cause, especially in elderly cats, but they can also be associated with a toxin.

Poorly managed diabetic cats can suffer from diabetic ketoacidosis with vomiting, lethargy and extreme dehydration. These cats may also be very thirsty. As this is a potentially life-threatening condition, diabetic cats need to have their blood glucose levels checked regularly. Any cat that is showing symptoms of diabetes, which includes increased hunger and thirst, should be tested by their veterinarian so it can be diagnosed and treated early.

Elderly cats with an overactive thyroid gland can present with vomiting as the only symptom. However, it’s more common for the vomiting to be accompanied by a ravenous appetite, weight loss and behaviour changes such as increased meowing or going to the toilet in strange places.

Cats with pancreatitis can become seriously ill, with both acute and chronic disease. These cats often have a fever and abdominal pain. Vomiting isn’t a constant feature and diagnosis isn’t always easy, though. Interestingly, it appears that pancreatitis is quite common in cats, with 45% of clinically normal cats showing signs of microscopic abnormalities when their pancreas was biopsied after they had passed away (4).

How to manage vomiting in cats

An acutely vomiting cat needs to be examined by their veterinarian to rule out serious causes such as pancreatitis or an intestinal foreign body. Treatments can range from the simple to the complex: such as worming treatments or withholding food for 24 hours to let the gastrointestinal tract settle down, or using intravenous fluids and even surgery to remove an obstruction.

Chronic vomiting is a more challenging condition to diagnose, however. Blood tests will be necessary and depending on the findings, an affected cat may also need an abdominal ultrasound and an intestinal biopsy. Treatments may include hypoallergenic diets, anti-inflammatory medication and possibly chemotherapy drugs if the diagnosis is cancer. Liver, kidney and thyroid disease are also diagnosed with blood tests, although they can be managed with changes in diet and fluid therapy. Cats with hyperthyroidism will need long term medication to regulate their thyroid hormone levels.

Vomiting is not uncommon in cats and its significance depends on how often it is occurring and if it is accompanied by other symptoms. A vomiting cat, however, should be examined by a veterinarian so the cause can be diagnosed and any necessary treatment can start as soon as possible, giving the best chance of a quick resolution to the problem.

1 Cannon, M. (2012). Hair Balls in Cats: A normal nuisance or a sign that something is wrong?. Journal of Feline Medicine and Surgery, 15(1), pp.21-29. 2 Norsworthy, G., Scot Estep, J., Kiupel, M., Olson, J. and Gassler, L. (2013). Diagnosis of chronic small bowel disease in cats: 100 cases (2008–2012). Journal of the American Veterinary Medical Association, 243(10), pp.1455-1461. 3 Huang-Komic, E. (1999). Chronic intermittent vomiting in a cat: a case of chronic lymphocytic-plasmacytic gastritis. Can Vet J, 40(3), pp.196-8. 4 De Cock, H., Forman, M., Farver, T. and Marks, S. (2007). Prevalence and Histopathologic Characteristics of Pancreatitis in Cats. Veterinary Pathology, 44(1), pp.39-49.

Author info: Dr Audrey Harvey is a graduate of the University of Queensland, Australia, and has worked in small animal practices for 25 years. She is particularly interested in obesity management and the role of exercise in resolving behaviour problems in dogs.

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Nothing beats a healthy, balanced diet to provide all the nutrients we need. But when this isn't possible, supplements can help. This article isn't intended to replace medical advice. Please consult your healthcare professional before trying supplements or herbal medicines.



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