Why Is My Cat Throwing Up? Causes and When to Worry

The short answer: most cats throw up now and then, often because they ate too fast, brought up a hairball, or nibbled grass or something they shouldn’t have. A single episode in a cat that is otherwise eating, playing and acting normally is usually nothing to worry about. Vomiting more than once a week, vomiting with blood, lethargy, diarrhoea or not eating, or repeated vomiting in one day needs a vet.

Is it vomiting or regurgitation?

It helps your vet if you can tell them which one you saw:

• Vomiting is active. Your cat usually drools, retches and heaves with its belly before bringing up partly digested food, liquid or foam.
• Regurgitation is passive. Food comes back up with little or no effort, usually soon after eating, and often still looks like the food that went down (sometimes in a tube shape).

PetMD describes the same difference: vomiting is forceful and the contents look digested, while regurgitation needs no force and the food is undigested. Regurgitating once after wolfing down a meal is common. Regular regurgitation can point to a problem with the oesophagus (food pipe), so mention it to your vet.

What the vomit looks like and what it may mean

What you see	What it often means
White foam or froth	An empty or irritated stomach. Common before breakfast, or with hairballs.
Yellow liquid (bile)	The stomach has been empty for a while. Often happens when meals are spaced far apart.
Clear liquid	Stomach fluid, or water drunk too quickly
Undigested food soon after eating	Eating too fast or too much (“scarf and barf”), or regurgitation
A tube of wet hair	A hairball
Green	Bile, or grass and plants your cat has eaten
Worms, like spaghetti	Roundworms. See our guide to worms in cats.
Red streaks or blood	Irritation or injury in the stomach or throat. Call your vet.
Dark brown, like coffee grounds	Possibly digested blood. See a vet the same day.
Brown and smelling like poop	Possibly a blockage in the intestines. See a vet the same day.

The colour and texture are clues, not a diagnosis. A cat that vomits once and seems completely fine afterwards usually is fine, whatever the colour. A cat that vomits repeatedly needs a vet whatever the vomit looks like.

Common reasons cats throw up

• Eating too fast or too much. The classic “scarf and barf”, often in multi-cat homes where cats race to finish first.
• Hairballs. Cats swallow a lot of loose hair when grooming, especially long-haired cats and in shedding season.
• A sudden change of food. Switching brands overnight can upset the stomach.
• Eating grass, plants or non-food items. Some houseplants are toxic, and lilies are deadly to cats. The FDA warns that eating even small parts of a lily, or drinking the vase water, can cause kidney failure. Vomiting is often the first sign.
• An empty stomach. Some cats bring up yellow bile or foam when they go too long between meals.
• Food intolerance or sensitivity to an ingredient in their diet.
• Worms, especially in kittens.
• Swallowed objects, such as string, hair ties, thread or tinsel. These can block or damage the intestines.
• Poisons, including human medicines, cleaning products, antifreeze and toxic foods.
• Underlying illness. The Cornell Feline Health Center lists kidney disease, hyperthyroidism, diabetes, inflammatory bowel disease, constipation and growths in the gut among the causes of vomiting. These are more common in middle-aged and older cats, and the vomiting can start long before other signs appear.

Why does my cat throw up after eating?

If your cat brings food back up within minutes of eating, but is otherwise well, it’s usually about how they eat rather than what they eat. Things that often help:

• Slow them down with a slow-feeder bowl or puzzle feeder, or by spreading wet food thinly on a flat plate.
• Feed smaller meals more often, for example three or four small meals instead of one or two large ones. This also helps cats that vomit yellow bile or foam on an empty stomach.
• Feed cats separately if one is gulping its food to beat the others.
• Change foods gradually over 7 to 10 days, mixing a little more new food in each day. Our kitten food guide has a simple changeover chart.
• Raise the bowl slightly, which some cats find more comfortable.

If your cat throws up after most meals, is losing weight, or the vomiting continues despite these changes, see your vet. Ongoing vomiting after eating can be a sign of a food intolerance, inflammatory bowel disease or another medical problem.

Hairballs: normal or not?

Cornell says that bringing up a hairball every week or two is common and usually not a problem. To reduce hairballs:

• Brush your cat regularly, daily for long-haired cats during shedding season. See our grooming guide.
• Try a hairball-control food or treat, if your vet agrees.
• Watch for blockages. A cat that retches repeatedly without bringing anything up, stops eating, or seems constipated may have a hairball or something else stuck. That needs a vet.

How often is too often?

According to Cornell, vomiting more than once a week should be checked by a vet. So should vomiting together with any of these, which Cornell lists as warning signs:

• lethargy or weakness
• eating less, or not eating
• blood in the vomit
• drinking more than usual
• changes in peeing
• diarrhoea at the same time

When to see a vet straight away

Contact your vet or an emergency clinic the same day if your cat:

• vomits several times in a few hours, or can’t keep water down
• has blood in the vomit, or vomit that looks like coffee grounds or smells like poop
• may have eaten string, thread, a hair tie, a toy, or anything else that could cause a blockage
• may have eaten lilies, medication, antifreeze, chemicals or a toxic plant
• is lethargic, weak, hiding or seems in pain (for example, a tense or tender belly)
• has vomiting and diarrhoea together
• has stopped eating for more than about a day
• is a kitten, an elderly cat, or has a known illness such as diabetes or kidney disease

If you see string or thread hanging from your cat’s mouth or bottom, don’t pull it. It can be anchored further inside, and pulling can seriously injure the intestines. PetMD treats swallowed objects as a medical emergency. Call your vet.

What to do at home after a single vomit

If your cat vomits once and otherwise seems normal:

1. Clean up and check what came up. Note the colour and contents, or take a photo for your vet.
2. Keep fresh water available.
3. Offer a small meal of their normal food after a few hours, rather than a big one.
4. Watch for a day. Note any more vomiting, whether they eat, and how their energy and litter tray habits look.

Never give your cat human medicines for nausea or upset stomachs unless your vet tells you to. Several common ones, including some stomach remedies, are dangerous for cats. Don’t withhold food for long either. Cats that stop eating for a few days can develop a serious liver condition, so a cat that hasn’t eaten for a day should see a vet.

Kittens that throw up

Kittens are small and can become dehydrated quickly, so it’s best to call your vet sooner rather than later. Common causes in kittens include worms, eating too fast, sudden food changes and swallowing small objects during play. For the first months, see our guide on how to look after a kitten.

The best food for a cat that throws up

There’s no single best food for every cat that vomits. The right one depends on the cause:

• Cats that eat too fast often do better with the same food served differently: in smaller meals, from a slow feeder, or as wet food.
• Cats with a sensitive stomach may suit a “sensitive stomach” formula, but change foods gradually.
• Cats with a suspected food intolerance usually need a vet-supervised diet trial, often with a prescription hydrolysed or limited-ingredient food.
• Cats with hairballs may benefit from a hairball-control formula and more brushing.

See our guide to choosing the best cat food, and talk to your vet before switching to a special diet.

FAQs

Is it normal for cats to throw up?

Occasional vomiting, such as a hairball every week or two or a single vomit after eating too fast, is common. Vomiting more than once a week, or with other signs like lethargy, diarrhoea or not eating, isn’t normal and should be checked by a vet.

Why is my cat throwing up white foam?

White foam usually comes from an empty or irritated stomach. It often happens before mealtimes or when a cat is trying to bring up a hairball. If it happens often or your cat seems unwell, see your vet.

Why is my cat throwing up yellow liquid?

Yellow liquid is usually bile, which often means the stomach has been empty for a while. Feeding smaller meals more often, including a small late meal, often helps. Repeated bile vomiting should be checked by a vet.

Why does my cat keep throwing up undigested food?

Usually because they’re eating too fast or too much, which brings the food straight back up. A slow feeder and smaller, more frequent meals often fix it. If it continues, see your vet.

Should I feed my cat after it throws up?

If your cat seems well, offer fresh water and a small portion of their usual food after a few hours. Don’t skip meals for long. A cat that won’t eat for more than about a day needs a vet.

When should I worry about my cat throwing up?

Worry if your cat vomits more than once a week, several times in one day, brings up blood, has diarrhoea too, stops eating, seems lethargic, or might have eaten string, a toxic plant like lilies, or medication.

Sources

• Cornell Feline Health Center: Vomiting
• PetMD: Cat vomiting: causes and types
• PetMD: Cat intestinal blockage
• FDA: Lovely lilies and curious cats: a dangerous combination