Why Is My Cat Vomiting? Causes, Treatments & When to See a Vet

Most cat parents know the feeling. Waking up in the middle of the night to the sounds of their cat doing what can only be described as a full body heave, summoning the contents of whatever their curiosity led them to eat just moments prior. Or walking into the lounge to see a mysterious puddle of yellow liquid with tufts of hair and mystery contents, dried into your beautiful carpet. Occasional vomiting in cats is common, but knowing whether your cat's sickness is normal or a sign of something more serious is what every pet parent needs to understand.

In the walls of my consultation room a common question is: "My cat is vomiting, should I be worried?" To which I'll often reply, "How often is it happening?", "What colour is the vomit?", "Is it after food or first thing in the morning?" The answer depends on so many factors. Vomiting is more of a symptom than a disease, but it signals when there could be something else going on with your cat.

This guide walks you through the major causes of cat vomiting, what to watch for, and when to call your vet.

Is It Normal for Cats to Vomit?

Occasional vomiting, once or twice a month, can be considered within the range of normal for some cats, especially the ones who eat everything in their food bowl without taking a breath, and our longer-coated cats who groom regularly. Hairballs and occasional stomach upsets happen from time to time. However, vomiting more than once a week, or any sudden increase in frequency (perhaps daily or every other day), always warrants further investigation.^[1]

Acute vomiting comes on suddenly and is usually short-lived. Chronic vomiting happens regularly over weeks or months and often suggests something else may be going on.

As a general guide:

• Occasional vomiting (once a week or less) with no other symptoms: monitor, but not immediately concerning
• Frequent vomiting (more than once a week): worth a vet call even if your cat seems otherwise well
• Vomiting with blood, lethargy, weight loss, or changes in appetite or litter tray use: contact your vet the same day
• Continuous vomiting or retching with nothing produced: emergency, contact your vet immediately

Common Causes of Cat Vomiting

1. Eating Too Fast

One of the most common reasons cats vomit is eating too quickly. When a cat hunches over their bowl and gobbles down their food, they swallow air along with it (aerophagy), which stretches the stomach and triggers the vomiting reflex almost immediately after eating. The vomit usually contains recognisable, undigested food. Not to be confused with regurgitation, where the vomit may come up as a sausage shape to match the oesophagus, rather than a puddle of vomit.

Solutions include using a slow-feeder bowl, which has bumps and grooves to deliberately make eating trickier and slow them down. Puzzle feeders work in a similar fashion and double up as a great form of enrichment for your cat. Spreading kibble on a flat surface, or offering smaller, more frequent meals throughout the day, also works quite well.

2. Hairballs (Trichobezoars)

Cats are fastidious groomers and we all enjoy watching them meticulously look after themselves, but all that loose fur has to go somewhere. Most of it passes through the digestive system, but some accumulates in the stomach and forms a hairball. When the hairball is too large to pass, the cat vomits it up, and in worst case scenarios an excessive amount of hair can cause an obstruction.^[2]

A typical hairball vomit looks tubular rather than round, compressed by the oesophagus (the pipe that connects the mouth to the stomach) on the way up.

Long-haired breeds (I'm looking at you long haired Angoras and Maine Coons) and cats that groom excessively are most prone. Regular brushing and hairball-control diets, or pastes that you can put on their paws to lick off, can help reduce frequency. Think less loose hair to lick up means fewer hairballs, and the pastes usually act as a lubricant to help smooth passage through the digestive tract rather than getting stuck in the stomach.

3. Dietary Indiscretion

We all know the saying about curiosity and cats. Eating grass, plants, bits of string, insects, or scavenged food they find outdoors can all cause a one-off bout of vomiting. This is usually self-limiting, which is the fancy way of saying that after a little benign neglect, the vomiting often resolves itself.

From time to time they will get into something they shouldn't, which is not the end of the world and can often be rectified with patience and gently feeding their normal food, little and often. If your cat is an outdoor cat or has access to houseplants, it is worth noting that several common plants are toxic to cats. True lilies (Lilium species) and daylilies (Hemerocallis) are particularly dangerous and can cause acute kidney injury, with vomiting often an early sign.^[3] Onions, garlic, chives and leeks (the Allium family) are also toxic, but their mechanism is different: they damage red blood cells and can cause anaemia rather than kidney damage.^[4] Either way, if you suspect ingestion, contact your vet without waiting.

4. Food Sensitivity or Intolerance

Some cats have digestive sensitivities to specific proteins or ingredients in their food. Unlike a true food allergy (which involves an immune response), food intolerance causes direct gastrointestinal irritation. I try to communicate this to clients by comparing the difference between a deathly nut allergy and a dairy intolerance. You may notice vomiting consistently after eating a particular food, often accompanied by loose stools or excessive gas, but it is rarely life-threatening.

An elimination diet, where we switch to a hypoallergenic or novel protein diet (insect, game, I have even had patients on alligator or kangaroo based diets), is the standard way to identify food sensitivities. The trial typically runs 8 to 12 weeks under veterinary guidance. In some cases other proteins can be reintroduced back into their diet afterwards.

5. Sudden Diet Changes

Cats have sensitive digestive systems and are very particular about what they eat. Switching foods too quickly, without transitioning, even from one good-quality food to another, can cause vomiting and diarrhoea. Any food change should be made gradually over 7 to 14 days, mixing increasing amounts of the new food with decreasing amounts of the old. Think old to new: 80:20, 70:30, 60:40, and so on, until you have weaned them over about 14 days.

6. Gastritis

Gastritis, simply put, is an inflamed stomach lining. It can be caused by something the cat ate, an infection, stress, or medication. Symptoms include vomiting (often yellow bile if the stomach is empty after long periods without food), reduced appetite, and lethargy. Mild cases usually resolve within 24 to 48 hours with a bland diet and plenty of water. Persistent gastritis needs veterinary investigation.

7. Intestinal Parasites

Roundworms, tapeworms, and other internal parasites can cause vomiting, particularly in younger cats or those with outdoor access, especially cats that have not been treated regularly for fleas or hunters. You may see segments of tapeworm in the vomit that look like grains of rice, or roundworms, which are typically whitish and spaghetti-like in appearance. If you notice weight loss, a pot-bellied appearance, or poor coat condition alongside the sickness, regular worming is essential. Consult your vet about a product that actually works for your cat's lifestyle, every 1 to 3 months for outdoor cats and depending on what flea treatment you are using.

8. Kidney Disease

The kidneys are a prominent organ commonly associated with chronic vomiting in older cats. As kidney function declines, waste products build up in the bloodstream (uraemia), causing persistent nausea and vomiting, often in the morning when the stomach is empty, producing white foam or yellow bile.^[5]

Other signs include increased thirst and urination, weight loss, reduced appetite, and lethargy. Kidney disease is one of the most important diagnoses not to miss, as it is fairly common in our senior cats.

9. Hyperthyroidism

Overactive thyroid glands are extremely common in middle-aged and older cats. Probably my most diagnosed disease in older cats. Whenever I hear the history of a vocal cat losing weight but with a ravenous appetite and hyperactive behaviour, I often think hyperthyroid. Hyperthyroidism speeds up the entire metabolism, which can cause vomiting, weight loss despite increased appetite, hyperactivity, and a scruffy coat. It is very manageable once diagnosed, with options including medication (oral or transdermal), a prescription iodine-restricted diet, surgery, or radioactive iodine therapy. Radioactive iodine is considered the gold-standard treatment and is becoming increasingly available at UK referral centres.^[6]

10. Inflammatory Bowel Disease (IBD)

IBD is a chronic condition where the walls of the digestive tract become infiltrated with inflammatory cells. It causes persistent vomiting and/or diarrhoea, weight loss, and variable appetite. Diagnosis usually requires intestinal biopsy, as it can be difficult to differentiate from diseases such as alimentary lymphoma. Management involves dietary modification and often long-term immunosuppressive medication.^[2]

11. Foreign Body Obstruction

If a cat swallows something it cannot digest (a piece of string, a toy, or the most common, hair ties), it can become lodged in the intestines and cause a blockage. This is a medical emergency and often warrants surgery to rectify. Signs include repeated, unproductive vomiting, abdominal pain, complete loss of appetite, and rapid deterioration. If you suspect a foreign body, go to the vet immediately.

12. Pancreatitis

Inflammation of the pancreas can cause acute vomiting, abdominal pain, lethargy, and loss of appetite. It can range from mild to life-threatening. Cats with pancreatitis often also have concurrent liver, biliary or intestinal disease due to their anatomy (sometimes called "triaditis"), and diagnosis typically requires blood tests and ultrasound.^[2]

What Does the Vomit Look Like? A Vet's Guide

Yellow or green bile: Stomach is usually empty. Your cat is most likely vomiting first thing in the morning, especially if they last ate quite early the evening before or have fasted for long periods. Can indicate gastritis, IBD, or a gap between meals that is too long.

White foam: Could be saliva, but could also be bile-like vomiting from an empty stomach.

Undigested food shortly after eating: Eating too fast, stress, or an oesophageal problem causing regurgitation.

Blood (bright red or dark brown "coffee grounds"): Immediate vet visit required. Could indicate stomach ulcers, foreign body, or a more chronic systemic disease.

Tubular mass of fur: Hairball. Expected, especially in long-haired cats.

Worms: Intestinal parasites. Definitely check with your vet, as vomiting worms could be a sign of a high parasite load, and a wormer will be required.

When Is Cat Vomiting an Emergency?

Seek emergency veterinary care if your cat is:

• Vomiting blood or vomit that looks like coffee grounds
• Vomiting repeatedly with no relief (more than 3 to 4 times in a few hours)
• Showing signs of abdominal pain: hunching, reluctance to be touched, crying out
• Vomiting alongside severe lethargy or collapse
• Unable to keep water down
• Vomiting after known ingestion of a toxin (lily, antifreeze, medications, onion/garlic)
• A kitten or elderly cat vomiting and deteriorating quickly

When Should You Call the Vet (Non-Emergency)?

Book a vet appointment within a few days if your cat:

• Vomits more than once or twice a week
• Has been vomiting for more than 2 to 3 days
• Is also losing weight or refusing food
• Is drinking more water than usual
• Has also developed diarrhoea
• Seems consistently uncomfortable or unwell

For a full guide to recognising signs of serious illness in cats, read our article on how to tell if your cat is in pain and our overview of cat illness symptoms and when to act.

What to Do at Home When Your Cat Vomits

For a single episode of vomiting with no other concerning signs:

• Withhold food for 2 to 4 hours to let the stomach settle (water is fine)
• Offer a small amount of their normal food; in some cases pet parents may choose a prescriptive or bland diet, but little amounts of their normal food is usually fine
• Monitor closely for the next 24 hours
• Keep a note of frequency, what the vomit looks like, and any other symptoms

Do not give human medications such as Pepto-Bismol, paracetamol, or ibuprofen. These are toxic to cats.^[7]

How Litter Sense Fits In

Honestly, Litter Sense is not going to help you work out why your cat is vomiting. Vomiting itself is a stomach-and-upper-GI issue, not something you will spot in the litter tray.

Where Litter Sense is useful alongside this topic is for the urinary side of things. Some conditions that can cause vomiting (particularly in severe cases, urinary blockage or advanced kidney disease) also change what happens in the litter tray. Litter Sense's colour-changing crystals may help pet parents flag changes in urine pH or the presence of blood, which can prompt a vet visit where the full picture, including the vomiting, can be investigated. It is a monitoring aid, not a diagnostic tool, and a colour change is a prompt to speak with your vet, not a diagnosis.

For more on how it works, read our complete guide on how Litter Sense monitors cat urinary health.

Frequently Asked Questions

Why does my cat vomit every day?

Daily vomiting is not normal and needs veterinary investigation. Common causes include kidney disease, hyperthyroidism, IBD, intestinal lymphoma, or a chronic dietary sensitivity. Discuss with your vet; sometimes a simple change can be an easy fix.

Why is my cat vomiting yellow liquid?

Yellow liquid is bile, produced by the liver and stored in the gallbladder. Cats vomit bile when their stomach is empty, often first thing in the morning or late at night. It can suggest the cat is going too long without food, or may have gastritis, IBD, or a chronic condition such as early kidney disease.

Why is my cat vomiting white foam?

White foam could be saliva, but could also indicate irritation from the stomach. It is worth discussing with your vet if your cat is frequently vomiting white foam.

Why does my cat vomit after eating?

Eating too fast is the most common cause. Regurgitation (undigested food brought up almost immediately) is different from true vomiting; it suggests a problem with the oesophagus rather than the stomach. Both warrant investigation if happening regularly.

Is it normal for cats to vomit hairballs?

The occasional hairball (once a month or so) is common, especially in long-haired cats. More frequent hairball vomiting can often be reduced with regular grooming and hairball-support diets. If your cat is having hairballs more than weekly, it is worth a vet check to rule out excessive grooming caused by anxiety or a skin condition.

What home remedy can I give my cat for vomiting?

The safest home approach is a short food fast (2 to 4 hours), followed by small amounts of their normal food (around a quarter of what you would normally give). If appetite needs stimulating, plain boiled chicken or a gastrointestinal diet from your vet can help. Never give human medications. If symptoms persist beyond 24 hours, or there are any other concerning signs, see a vet.

Can stress cause a cat to vomit?

Yes. Cats are sensitive to environmental change, and stress from moving home, a new pet, changes in routine, or loud events can trigger vomiting. Stress-related vomiting usually resolves when the stressor is removed, but persistent stress warrants attention.

Could my cat's vomiting be related to their litter tray habits?

Sometimes, yes. Kidney disease, one of the common causes of chronic vomiting in older cats, also tends to cause increased thirst and urination, and changes in urine concentration. Stressed cats can also show urinary signs (such as blood in the urine from feline idiopathic cystitis) alongside behavioural changes. Monitoring litter tray output is a genuinely useful part of keeping track of your cat's health.

References

1. Cornell Feline Health Center. Vomiting. Available at: https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center
2. Merck Veterinary Manual. Disorders of the Stomach and Intestines in Cats. Available at: https://www.merckvetmanual.com/cat-owners/digestive-disorders-of-cats/disorders-of-the-stomach-and-intestines-in-cats
3. International Cat Care. Lily poisoning in cats. Available at: https://icatcare.org/articles/lily-poisoning-in-cats
4. Cortinovis C, Caloni F. Household Food Items Toxic to Dogs and Cats. Frontiers in Veterinary Science, 2016. Available at: https://doi.org/10.3389/fvets.2016.00026
5. International Renal Interest Society (IRIS). IRIS Staging of CKD. Available at: http://www.iris-kidney.com/guidelines/staging.html
6. Carney HC, Ward CR, Bailey SJ, et al. 2016 AAFP Guidelines for the Management of Feline Hyperthyroidism. Journal of Feline Medicine and Surgery, 2016. Also: UK Vet Companion Animal, Radioiodine treatment for hyperthyroid cats: frequently asked questions from vets and clients. Available at: https://www.ukvetcompanionanimal.com/content/clinical/radioiodine-treatment-for-hyperthyroid-cats
7. Veterinary Poisons Information Service (VPIS) and International Cat Care. Common human medications toxic to cats. Available at: https://icatcare.org/articles/poisons