What is gastroenteritis in cats?

If your usually playful cat suddenly becomes lethargic, refuses food, or develops vomiting or diarrhoea, gastroenteritis could be the culprit. This condition, which refers to inflammation of the stomach and intestines, can appear suddenly and leave even the healthiest cats feeling miserable.

While many cases resolve with prompt care, understanding the signs, causes, and treatment options can help you act quickly and keep your feline friend comfortable.

Gastroenteritis can occur at all ages and stages of life, and it can be an acute condition, coming on seemingly out of nowhere, or chronic, where it develops more slowly and persists for longer.

Acute gastroenteritis

Acute gastroenteritis is a sudden-onset condition and is often caused by eating harmful items (e.g. table scraps or garbage), infections such as parvovirus or protozoa infestation (e.g., Giardia), or even stress.

Treating Giardia often includes a prolonged use of a worming agent combined with antimicrobial treatment. The average treatment cost for Giardia in 2024 was $580 but could be as high as $8,542^Ø.

Chronic gastroenteritis

Chronic gastroenteritis develops over time and is typically triggered by food allergies, underlying diseases, or persistent exposure to stressors.

The average treatment cost for IBD (inflammatory bowel disease) in 2024 was $1,701, with the highest amount being $25,703^Ø.

How common is gastroenteritis in cats?

Gastroenteritis is one of the most common conditions experienced by cats. It can affect felines of all ages and breeds, but is more prevalent in kittens and senior cats, and it does occur more often in some breeds than others:

Cost of gastroenteritis treatment for cats

According to PetSure claims data in 2024, gastroenteritis is the most claimed condition in cats.

The average cost for treatment in cats in 2024 was $735, with the highest cost for treatment reaching as much as $26,987^Ø.

As you can see from the table below, the cost of treating gastroenteritis has increased steadly from year to year.

Symptoms of gastroenteritis in cats

Signs of gastroenteritis in cats often develop quickly and may include:

• Vomiting (sometimes containing undigested food, foam or bile)

• Diarrhoea, which may contain mucus or blood

• Loss of appetite (accompanied by weightloss in longer term cases)

• Lethargy or weakness, reduced physical activity

• Abdominal pain or bloating

• Dehydration (dry gums, sunken eyes)

• Fever (in infectious cases)

• Hiding behaviour
• Reduced grooming 

When to visit the vet

While mild cases may resolve on their own, there are a number of symptoms that indicate a more serious condition.

You should seek veterinary advice if your cat:

• Has repeated or severe vomiting or diarrhea

• Shows signs of pain, lethargy or distress

• Refuses food or water for more than 24 hours

• Has blood in their vomit or stools

• Is a kitten, senior or has existing health conditions

Unsure how serious it is?

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Causes of gastroenteritis in cats

Gastroenteritis in cats can occur for many reasons, ranging from something as simple as eating spoiled food to more serious infections or underlying health conditions.

Here are some of the key reasons why cats develop this condition:

• Dietary indiscretion – eating spoiled food, garbage, and certain human foods.

• Hairballs or foreign bodies – Non-food items like fur, plants or string can irritate the gut.

• Dietary changes or intolerances – a sudden switch in diet or food allergies can upset digestion.

• Infections – viral (e.g., feline panleukopenia), bacterial (e.g., Salmonella), or parasitic (e.g., roundworms, giardia) infections are common culprits.

• Toxins or poisons – ingesting poisonous plants, medications, cleaning products, or human foods (like onions or chocolate) can cause severe irritation.

• Stress – cats are highly sensitive to stress, and changes in routine or environment can trigger gastrointestinal upset.

• Underlying diseases – conditions such as kidney disease, pancreatitis, or inflammatory bowel disease may present with similar symptoms.

Diagnosis of gastroenteritis in cats

Early and accurate diagnosis not only ensures appropriate treatment but also minimises the risk of complications, especially in vulnerable groups like kittens and senior cats.

To confirm gastroenteritis and rule out other underlying conditions, your vet may conduct a variety of diagnostic tests, including:

Physical exam and history

Because gastroenteritis can be caused by many different factors, your vet will start with a physical examination, which may include checking hydration, abdominal pain, temperature, and overall condition.

The vet will also take a detailed history of your cat’s recent diet, environment, and symptoms. This helps identify potential triggers, such as sudden dietary or environmental changes, scavenging, or toxin exposure.

Other diagnostic tests

Your vet may recommend one or more of the following tests to help identify the cause of the problem:

• Blood tests – to assess organ function, hydration levels, and detect signs of infection or inflammation.
• Urinalysis  – to assess kidney function and help to rule out other conditions, such as kidney disease, that can mimic gastroenteritis symptoms.
• Stool sample – to identify the presence of parasites, bacterial overgrowth, or evidence of an infection.
• Imaging techniques (X-rays or ultrasound) – these are used if a foreign object, blockage, or more serious underlying condition is suspected; they can also help detect abnormalities in the gastrointestinal tract.
• Endoscopy – allows visual examination of the GI tract and, in some cases, biopsy collection to investigate chronic or severe cases and to retrieve some foreign bodies.

Treatment of gastroenteritis in cats

The treatment plan depends on the severity of symptoms and underlying cause, but the main goal is to restore hydration, ease discomfort, and allow the digestive system to recover.

Mild cases of gastroenteritis in cats usually resolve with supportive care, while moderate to severe cases require more medical interventions. Untreated or chronic cases can lead to complications, so early detection and tailored management are both essential.

Initial treatment usually focuses on stabilizing the cat:

• Withholding food temporarily – followed by a bland, easily digestible diet (under veterinary advice).

• Fluid therapy to treat or prevent dehydration and electrolyte imbalances.

• Antiemetics to reduce vomiting.

• Probiotics to support gut health and restore balance.

Once the underlying cause is identified:

• Parasites are treated with appropriate antiparasitic medications.

• Bacterial infections may require antibiotics, though many mild cases resolve with supportive care

• Underlying diseases are treated appropriately (e.g. kidney disease or pancreatitis).

• Foreign bodies or obstructions may require surgical removal.

Home care for cats with gastroenteritis

Most cats start to feel better within a few days once treatment begins, but careful home management is important to ensure full recovery and prevent relapses.

While your vet will guide you on specific home care, here are some general tips:

• Offer fresh water at all times to prevent dehydration

• Feed only what your vet recommends (usually a bland or prescription diet)

• Monitor your cat closely for signs of improvement or worsening symptoms

• Keep your cat indoors and away from stressors until they recover

• Ensure medications are given as prescribed

Prevention of gastroenteritis in cats

While not every case of gastroenteritis can be prevented, there are several steps you can take to reduce your cat’s risk:

• Avoid sudden changes in diet – transition gradually to a new type of food over 7 to 10 days

• Keep your cat indoors or supervise outdoor time to avoid scavenging

• Ensure your cat doesn’t have access to toxins, medications or human foods

• Provide routine parasite control and regular veterinary check-ups

• Keep their environment calm, especially during times of change or stress

• Ensure they are up to date with vaccinations

In summary…

Gastroenteritis in cats refers to inflammation of the stomach and intestines. This condition can cause vomiting, diarrhea or both, and is often accompanied by abdominal discomfort, lethargy and a loss of appetite. It can be acute (sudden and short-term) or chronic (ongoing or recurring).

While most cases are mild and resolve with prompt treatment, gastroenteritis can sometimes indicate a more serious underlying problem, especially if symptoms are severe or persist. If your cat is showing signs of gastroenteritis, it’s important to monitor them closely and consult your vet for advice.

^∅Based on PetSure claims data, 2024 calendar year. Reimbursement for these claims under a pet insurance policy, would be subject to limits, such as annual benefit limits or sub-limits, benefit percentage, applicable waiting periods and any applicable excess. Cover is subject to the policy terms and conditions. You should consider the relevant Product Disclosure Statement or policy wording available from the relevant provider. Please note that values calculated are based on all claims for that condition and medically related conditions in each calendar year.