Most cat owners clean up vomit now and then, and it’s easy to assume it’s just part of having a cat. A single episode in a cat that then eats and acts normally often isn’t serious. But vomiting regularly, even hairballs, isn’t normal, and some vomiting is a sign of a problem that needs a vet quickly. Knowing what to look at, and when to act, makes the decision much easier.
Quick answer: One vomit in a cat that then eats, drinks and behaves normally can usually be watched at home. Call your vet if your cat vomits more than twice in 24 hours, vomits blood, stops eating, seems lethargic, has diarrhea too, or vomits regularly over weeks, even just once a week. Go to a vet straight away if vomiting won’t stop, your cat is weak, or you think it ate string, a toxin or a foreign object.
Vomiting or regurgitation?
It helps to know which one you are seeing, because the causes differ.
- Vomiting is active. You will usually see heaving, retching or belly contractions first, and what comes up is often partly digested food or liquid.
- Regurgitation is passive. Food comes back up with little effort, often soon after eating and usually looking undigested, sometimes in a tube shape.
Coughing can look similar too: a cat crouched low with its neck stretched out, hacking, may be coughing rather than vomiting. Coughing can be a sign of asthma or other breathing problems. If you’re not sure what you’re seeing, take a short video for your vet. Our guide to hairballs or coughing in cats explains the difference.
Common causes of vomiting in cats
Sudden (acute) vomiting
- Eating something it shouldn’t, such as spoiled food, plants, grass or something from the trash. Cornell vets say this is the most common cause.
- Eating too fast or eating too much at once, which often leads to regurgitation soon after a meal.
- A sudden diet change. Switching foods abruptly can upset the stomach; see how to change cat food safely.
- Hairballs, especially in long-haired cats.
- Intestinal parasites. See worms in cats.
- Infections of the stomach or gut.
- Toxins, including lilies, some household products and human medicines. See plants and foods poisonous to cats.
- Swallowed objects, such as string, thread, hair ties or toy parts, which can cause a blockage.
- Pancreatitis, inflammation of the pancreas.
Ongoing (chronic) vomiting
Vomiting that keeps coming back over weeks or months often has an underlying medical cause, such as food allergies or sensitivities, inflammatory bowel disease, kidney disease, an overactive thyroid (common in older cats), liver disease or certain cancers. These are more likely in middle-aged and senior cats, and many can be managed well once diagnosed. See common health problems in senior cats.
Are hairballs normal?
Hairballs are a type of vomiting. They are more common in long-haired cats and during heavy shedding. An occasional hairball isn’t usually a worry, but frequent ones are worth discussing with your vet, as they can make cats feel unwell and may point to overgrooming or a gut problem. Regular brushing helps; see how often to brush a cat.
What the vomit can tell you
| What you see | What it may mean |
|---|---|
| Undigested food soon after eating | Often regurgitation, eating too fast, or a sensitive stomach |
| Hair in a sausage shape | Hairball |
| Yellow or green liquid | Bile, often when the stomach is empty |
| White foam | Stomach or gut irritation |
| Red blood or streaks | Irritation or ulcers; call your vet |
| Dark brown or black, like coffee grounds | Digested blood; call your vet straight away |
| Worms | Parasites; call your vet |
How often is too often?
Cornell’s Catwatch notes that vomiting once a week is not normal and can signal a chronic problem. PetMD advises a vet workup for a cat vomiting about once or twice a week over several weeks, and a call to your vet if a cat vomits more than twice in 24 hours or two or three times in a row. A single episode in a cat that eats, keeps food down and acts normally may not need a visit, but keep an eye on it.
What to do at home
If your adult cat has vomited once or twice but is otherwise bright, alert and behaving normally:
- Watch closely for the next 24 hours. Note how often it vomits and what comes up. Photos help your vet.
- Make sure fresh water is available.
- Ask your vet about food. Cornell’s Catwatch mentions that for a cat that vomits but otherwise seems normal, food can be held back for about six hours and then a small meal offered. Check with your vet first, especially for kittens, senior cats and cats with diabetes, kidney disease or other conditions. Don’t hold back food for long: cats that don’t eat can become seriously ill.
- Don’t give human medicines. Over-the-counter remedies for people can be dangerous for cats. Only use medicines your vet prescribes.
- Check for hazards like string, hair ties, chewed plants or opened packets.
When to call the vet
Call your vet if:
- Your cat vomits more than twice in 24 hours or keeps vomiting
- Vomiting lasts more than a day
- There is blood in the vomit
- Your cat stops eating, seems lethargic or hides
- There is diarrhea too, which speeds up dehydration
- Your cat is losing weight or vomits regularly over weeks
- Your cat has a long-term condition such as kidney disease, diabetes or hyperthyroidism and starts vomiting
- A kitten is vomiting, since kittens dehydrate quickly
Urgent: go to a vet now if vomiting won’t stop, there is dark or a lot of blood, your cat is weak, collapsed or has a painful belly, may have swallowed string or another object, or may have eaten something poisonous. Repeated vomiting together with straining in the litter box can mean a urinary blockage, which is an emergency.
Signs of dehydration include sticky gums, sunken eyes and skin that doesn’t spring back quickly when gently lifted. For other warning signs, see signs your cat is sick, and for pain, signs your cat is in pain. If your cat is drinking less than usual, our guide on why your cat is not drinking much water may help, and if litter box habits have changed, see cat peeing outside the litter box.
What the vet may do
Your vet will ask how often it happens, what comes up, how your cat is eating and drinking, and about diet, treats, parasite control and any chance of eating something unusual. Depending on the findings, they may suggest blood and urine tests, a fecal test, X-rays or an ultrasound. Treatment depends on the cause and can include anti-nausea medicine, fluids for dehydration, a diet change, parasite treatment, or surgery for a blockage.
Frequently asked questions
Is it normal for a cat to vomit once a week?
No. Regular vomiting, even once a week, is not considered normal and can be a sign of an ongoing problem such as food sensitivity, gut disease or thyroid or kidney disease. Talk to your vet, especially if it has been going on for several weeks.
Why is my cat throwing up undigested food?
Undigested food soon after a meal is often regurgitation, commonly from eating too fast or too much at once. Smaller, more frequent meals or a slow feeder can help. If it happens often or your cat is losing weight, see your vet.
Why is my cat vomiting yellow liquid?
Yellow or green liquid is usually bile, which often appears when the stomach is empty. An occasional episode may not be serious, but if it happens regularly or your cat seems unwell, contact your vet.
Can I give my cat medicine for vomiting at home?
No, not without your vet’s advice. Many human medicines are harmful to cats. Your vet can prescribe safe anti-nausea treatment if it’s needed after finding the cause.
