Gastroenteritis in Cats: Symptoms, Causes, Treatment, and When to See a Vet

Gastroenteritis in cats is inflammation of the stomach and intestines that causes vomiting, diarrhea, and often a cat that stops eating. Most mild cases settle quickly with fluids and gentle food, but dehydration can build fast, and a cat that refuses food needs attention sooner than most owners expect.

This guide explains what gastroenteritis in cats looks like, how an indoor cat picks it up, what your vet does to treat it, how to care for your cat at home, how long it should last, and the signs that mean you should call the clinic today.

What Is Gastroenteritis in Cats?

Gastroenteritis in cats is inflammation of the stomach and intestines, and vomiting with diarrhea is how it usually shows, according to VCA Animal Hospitals. Most acute cases improve rapidly once the cat is rehydrated. A cat not eating for 24 hours, or any sick kitten, needs a vet.

Vets call it a diagnosis of exclusion. That means your vet rules out more serious problems, such as a swallowed object, a toxin, or pancreatitis, before settling on gastroenteritis as the explanation. A sudden, short bout is called acute gastroenteritis, and it is the most common form owners see.

Is gastroenteritis in cats serious? Usually not, when it is caught early. VCA reports that most acute cases improve rapidly after rehydration, which is why keeping a sick cat drinking matters so much in the first day.

From ChewyIn stock

Petlibro Stainless Steel Dog & Cat Fountain, 101-oz

A quiet 3 L stainless steel fountain with filtered moving water can help encourage a recovering cat to keep drinking.

$39.99

4.0

Buy on Chewy

Webvet may earn a commission when you click through to Chewy, at no extra cost to you.

Some cases are more involved. Chronic gastroenteritis in cats describes signs that keep returning over weeks rather than clearing up. You may also see the terms hemorrhagic gastroenteritis in cats, used when there is blood in the vomit or stool, and eosinophilic gastroenteritis in cats, a specific type of inflammation a vet confirms with testing.

Both of those forms need a vet's workup rather than home care. VCA lists blood in vomit as a reason to seek veterinary care immediately. Stories from other owners on forums such as Reddit can be reassuring, but they cannot tell you whether your own cat's case is the simple acute kind or one of these.

Symptoms of Gastroenteritis in Cats

The main symptoms of gastroenteritis in cats are vomiting and diarrhea, often in intermittent episodes rather than one constant stream. VCA describes this on-and-off pattern as typical. Common cat gastroenteritis symptoms include:

• Vomiting food, foam, or bile
• Loose or watery diarrhea
• Loss of appetite or refusing favorite foods
• Lethargy and hiding
• Belly discomfort, such as a hunched posture
• Dehydration, such as tacky gums and less urine in the litter box

If your cat is doing both at once, our guide to a cat throwing up and diarrhea walks through the combined picture. For loose stool alone, see why your cat has diarrhea and what to do about it.

From ChewyIn stock

Weruva Pumpkin Patch Up! Dog & Cat Food Supplement, 2.80-oz, 12 ct

A pumpkin supplement to ask your vet about for digestive support.

$17.88

Buy on Chewy

Webvet may earn a commission when you click through to Chewy, at no extra cost to you.

Dehydration is the symptom that turns a mild case into a serious one. VCA notes that dehydration can occur quickly if vomiting and diarrhea persist for more than 24 hours. VCA also lists loss of appetite among the warning signs that need prompt care when a cat is vomiting.

What are the first signs of gastroenteritis in cats?

The first signs are usually vomiting and loose stool that come and go, which VCA describes as intermittent episodes. Many owners notice a skipped meal or a cat that seems quieter than usual around the same time. Watch for lethargy, fever, or a refused meal alongside the vomiting, since VCA lists those as reasons to call the vet promptly.

How do cats act when their stomach hurts?

Cats tend to hide discomfort, so the signs are often behavioral. A cat with belly pain may:

• Sit hunched or curled tightly instead of stretching out
• Hide, avoid being picked up, or react when the belly is touched
• Walk up to the food bowl and then turn away
• Lick its lips or drool, which can come before vomiting

VCA lists abdominal pain with vomiting as a reason to seek veterinary care immediately, so a cat that seems sore and is also vomiting should be seen.

What Causes Gastroenteritis in Cats?

The usual cause of gastroenteritis in cats is something that irritates or infects the gut, and VCA names infection with bacteria, viruses, or parasites, certain medications, and even new foods. Many of the common causes of gastroenteritis in cats are minor, but a few are not.

VCA divides the causes of vomiting into two groups:

• Minor causes: intestinal parasites, dietary indiscretion (eating something it should not), hairballs, and food intolerance or allergy
• Serious causes: infections, toxins, pancreatitis in cats, cancer, and a foreign body blocking the intestines

A diet change made too fast is an everyday trigger, which is why vets recommend switching foods gradually. Parasites matter too: VCA lists coccidia and worms such as hookworms and roundworms among the infectious causes of diarrhea.

The Cornell Feline Health Center describes a hairball as a damp, cylindrical wad of undigested hair. Hairballs explain some vomiting, but they should not be blamed for repeated episodes. Our cat throwing up guide helps tell a hairball from something more.

How Do Indoor Cats Get Gastroenteritis?

Indoor cats get gastroenteritis mainly from what reaches them inside the home: new or spoiled food, toxic plant leaves, human medications, and germs carried in by a new cat or on objects.

How does an indoor cat get gastroenteritis?

An indoor cat usually gets gastroenteritis from something it ate or something brought into the house. VCA lists new foods as a trigger, and Cornell adds spoiled cat food, leaves of poisonous plants, and human medications. The panleukopenia virus can persist in the environment for more than a year, according to the Merck Veterinary Manual, so a new cat or contaminated item can carry it indoors.

Plants deserve special care. Cornell names poisonous plant leaves as a cause of vomiting, and some houseplants and bouquets are far more dangerous than an upset stomach. Read are lilies toxic to cats before keeping any in the house.

Any new food, including a switch to raw food, and any spoiled food can upset an indoor cat's stomach and intestines. The table below matches each indoor cause with the clue it tends to leave and how quickly to act.

How Is Gastroenteritis in Cats Diagnosed?

Gastroenteritis in cats is diagnosed by ruling out other causes, starting with a history and physical exam. Your vet will ask about diet changes, plants, medications, new pets, and how often your cat has vomited.

From there, testing depends on how sick your cat is. Cornell explains that bloodwork and fecal testing help rule out toxins, parasites, and metabolic disease. Common steps include:

• Fecal test: VCA says it detects intestinal parasites such as roundworm, hookworm, and giardia
• Bloodwork: helps rule out toxicities and metabolic diseases, per Cornell
• X-rays and ultrasound: Cornell notes these help find masses and foreign objects

A bright cat with one or two episodes may need only an exam. Bloodwork or imaging becomes more likely when vomiting is repeated, a swallowed object is possible, the cat is not eating, or signs return after treatment.

From ChewyIn stock

Hill's Prescription Diet i/d Gastrointestinal Health Cat Food, 4-lb

Hill's i/d is a highly digestible diet to ask your vet about during recovery.

$37.99

Buy on Chewy

Webvet may earn a commission when you click through to Chewy, at no extra cost to you.

What gets mistaken for gastroenteritis in cats?

Several conditions cause the same vomiting and diarrhea, which is why vets treat gastroenteritis as a diagnosis of exclusion. VCA and Cornell point to these look-alikes:

• Pancreatitis: VCA lists it among the serious causes of vomiting
• A foreign body: a swallowed object that blocks the intestines, which x-rays and ultrasound can find, per Cornell
• Feline panleukopenia: a contagious virus that starts with fever, depression, and appetite loss, according to Merck
• Hairballs: Cornell describes these as wads of undigested hair, and they can explain occasional vomiting
• Toxins, metabolic disease, and cancer: bloodwork and imaging help rule these out

Telling them apart at home is not possible, so repeated vomiting or a cat that stops eating needs an exam.

Treatment for Gastroenteritis in Cats

Treatment for gastroenteritis in cats centers on rehydration and restoring electrolyte balance, which VCA calls the principal treatment. The rest of feline gastroenteritis treatment depends on the cause and how sick your cat is.

To treat it, your vet usually combines some of these:

• Fluids: to rehydrate, with hospitalization for IV fluids when dehydration is significant, per VCA
• Anti-nausea medication: VCA names maropitant citrate (Cerenia) for minor vomiting cases, and Cornell notes anti-emetics are used in dietary indiscretion
• A veterinary gastrointestinal diet: VCA advises feeding small amounts of a diet made for gut problems
• Dewormers or anti-diarrheals: when parasites or persistent diarrhea are involved

VCA also lists probiotics among diarrhea treatments, with the advice to check with your vet before giving any supplement. Ask whether a product such as Purina Pro Plan FortiFlora Probiotic Supplement for Cats fits your cat; our cat probiotics guide explains how these products are used.

Treating your cat at home is reasonable only if it is still bright, drinking, and keeping some food down. The next section explains home care step by step, but a cat that is lethargic, dehydrated, or refusing food needs the clinic first.

Home Care for a Cat With Gastroenteritis

Home care for a cat with gastroenteritis means keeping water available, offering small bland meals, and watching closely for signs that it is getting worse. VCA says water should be freely available because it is needed to prevent dehydration.

Vet-recommended

From ChewyIn stock

Purina Pro Plan FortiFlora Probiotic Supplement for Cats, 30 ct

FortiFlora is a probiotic powder for cats that you can ask your vet about adding to a bland diet during recovery.

$30.99

4.7

Buy on Chewy

Webvet may earn a commission when you click through to Chewy, at no extra cost to you.

VCA notes that food may be withheld for 8 to 12 hours in the early stage of treatment. Do not stretch that further on your own. Cats risk hepatic lipidosis when they go without food, so any pause in feeding should be short and agreed with your vet.

When you restart food, follow these steps:

1. Offer an easily digested, bland diet, which VCA recommends for vomiting cats
2. Feed small meals several times a day instead of one large meal
3. Use a vet GI diet such as Hill's Prescription Diet i/d Gastrointestinal Health Cat Food if your vet recommends one
4. Once stools return to normal, transition back to the regular food over seven to ten days, as VCA advises

Keep a simple log of vomiting, stool, food eaten, and water intake. It helps your vet judge progress if you need to call.

A clean, steady water source helps too.

How Long Does Gastroenteritis Last in Cats?

The length of gastroenteritis in cats varies with the cause, and veterinary references do not give a fixed recovery time. VCA instead sets a checkpoint: call your vet if vomiting and diarrhea do not improve significantly within 24 to 48 hours of treatment.

VCA gives two more limits worth knowing:

• A cat that otherwise seems well but keeps vomiting for more than one to two days should see a vet
• Frequent liquid or semi-liquid stools lasting more than two days need a veterinary consult

Recovery time is usually short for a cat with a simple dietary upset, since most acute cases improve rapidly once rehydrated. If your cat stops eating at any point, our cat not eating guide explains why that changes the timeline.

Is gastroenteritis in cats fatal? Mild acute cases rarely are. The danger comes from severe dehydration, infections such as panleukopenia, and hepatic lipidosis in cats that stop eating, which is why the clock matters more than the diagnosis name.

Track three things each day of recovery: whether vomiting is less frequent, whether stools are firming up, and whether your cat is eating and drinking. Steady progress on all three is the pattern you want. A cat that improves and then relapses needs a recheck, since returning signs can point to a cause that has not been found yet.

Is Gastroenteritis in Cats Contagious?

Gastroenteritis in cats is contagious only when the cause is infectious, such as a virus, bacteria, or parasites. Cases caused by a diet change, a hairball, or a toxic plant cannot spread to other cats.

The most important contagious cause is feline panleukopenia. The Merck Veterinary Manual describes it as a highly contagious, often fatal viral disease of cats. Key facts from Merck:

• Cats are infected through the mouth and nose by exposure to infected animals
• Fever, depression, and loss of appetite appear after a 2 to 7 day incubation period
• The virus can persist in the environment for more than a year
• Vaccines provide solid, long-lasting immunity

If one cat in a multi-cat home is sick, keep it apart from the others and ask your vet whether testing is needed. Keeping your cats current on vaccines is the best protection against panleukopenia.

Because the virus survives so long in the environment, a cat can be exposed without ever meeting a sick animal. Bedding, carriers, and bowls that came from a home or shelter with an infected cat can carry it, which is one more reason to vaccinate cats that never go outside.

If your vet mentions FIP, or you are wondering how an indoor cat could catch it, what the early signs are, and whether vaccinated cats are protected, our guide to FIP in cats answers those questions. If you also share your home with a dog, the symptoms in dogs are covered in gastroenteritis in dogs.

When to See a Vet

See a vet the same day if your cat with gastroenteritis is lethargic, refusing food, dehydrated, vomiting blood, or is a kitten. VCA advises immediate care when a vomiting cat also has fever, lethargy, loss of appetite, abdominal pain, diarrhea, dehydration, blood in the vomit, or may have swallowed a foreign object or toxin.

The University of Illinois College of Veterinary Medicine lists jaundice (yellowing of the skin), lethargy, weakness, and vomiting as possible signs of hepatic lipidosis. Its standard treatment is feeding through a feeding tube, and many cases resolve after days to weeks. A cat not eating and lethargic should never wait.

Use this checklist for a same-day call:

• Your cat has not eaten in 24 hours, or eats far less than usual
• Vomiting or diarrhea contains blood
• Your cat is weak, hiding, or lethargic
• Gums look yellow, which can signal jaundice
• You suspect a swallowed toxin, plant, medication, or object
• The patient is a kitten, or an unvaccinated cat recently met a new cat

Also book a visit if your cat vomits more often than once a week, which Cornell says warrants a vet exam even when the cat seems fine. Severe panleukopenia needs hospitalization with IV fluids and supportive care, according to Merck.

Gastroenteritis in Cats FAQs