Why is Your Cat Vomiting?

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17 May 2024

Why is Your Cat Vomiting?

Anyone who has owned a cat knows the sound of a retching cat and what immediately follows. While vomiting isn’t necessarily unusual for many cats sometimes. However, if your cat is sick frequently or displays any other symptoms such as diarrhoea, lethargy, or stress, then it might be a sign something is wrong.  

Here, we’re going to talk you through the main types of cat vomit colour you might encounter as a new or existing cat owner, and what they mean.

Why Cats Vomit

As with humans and other animals, cats vomit when they feel nauseous, which may be related to their diet, health, or grooming standards. If your cat is bright and otherwise healthy, vomiting once is not cause for concern.  

If you're ever worried about your cat vomiting or if they're vomiting more than usual, you should contact your vet for advice. Sometimes, they can tell you over the phone whether or not your cat needs to be seen, but they'll need as much detail as you can gather. Taking pictures of your cat's vomit can be a huge help here if you're struggling to describe it, which, unfortunately, means getting up close with the upchuck. 

Cat vomit colour chart ukCat vomit colour chart uk

Cat Vomit Colour Chart

You should look out for a few things in your cat’s vomit to gauge whether or not something is wrong. However, this guide is not conclusive, and you know your cat best. If your cat is showing any other symptoms of health conditions, you should always take those into account as well when deciding whether to contact a vet.  

If your cat is sick, keep an eye out for the following:

  • Diarrhoea 
  • Lethargy
  • Weight loss/ lack of appetite
  • Behavioural changes (hiding, excessive grooming, urination outside litter boxes, etc.)
  • Vocalisations
  • Signs of pain, including not letting you touch their stomach or other areas.  

If you notice any of the above symptoms, as well as vomiting, you should consult with your vet as soon as possible to have your cat examined.

1. Cat Hairball or Vomit? 

Perhaps the most common kind of cat vomit is hairballs. These are a culmination of the hair your cat has swallowed during grooming, which clumps together in its stomach and irritates its sensitive stomach lining. Your cat will then vomit this hair instead of passing it through the digestive tract normally. 

The way to identify a hairball is if their vomit has clumps of compacted hair and clear, white, or yellow liquid 

While hairballs are natural in many cats, they shouldn’t be too frequent. If your cat coughs up hairballs frequently, this could be a sign that something is wrong with its stomach lining or that it is over-grooming in response to stress or a skin condition.   

Contact your vet if you notice your cat vomiting hairballs too frequently so they can evaluate your cat’s condition and offer recommendations.  

Preventing Hairballs in Cats

Not every cat is prone to hairballs, but those with thicker, longer coats may experience them more often than other cats. You can help reduce cat hairballs by regularly grooming your cat, switching to a hairball cat food like the Hill's™ SCIENCE PLAN™ Specialty Hairball Cat Food, or introducing hairball supplements for cats 

2. Cat Vomiting Yellow Liquid

Throwing up yellow liquid is also relatively common in cats. The yellow liquid is bile, which is the liquid produced by the liver and stored by the gallbladder. Bile's fundamental use is digestion by breaking down fats in food into fatty acids that can then be absorbed into the body.  

Cats throwing up bile can sometimes be a sign that they are vomiting on an empty stomach, which leaves the question of why they’re throwing up at all. It could be that your cat has smelled something particularly nasty to them, which may induce vomiting, or it could be a sign of something more serious, including endocrine problems or liver disease.  

If your cat is otherwise healthy and only throws up bile once, it may not require veterinary attention. However, if it happens more than once or your cat displays other symptoms, contact your vet as soon as possible for a consultation. It’s always better to be safe than sorry.  

3. Cat Vomiting Clear Fluid

If your cat vomits clear liquid, this is typically a sign that they are vomiting on an empty stomach. The most notable cause of cats vomiting clear liquid is internal parasites, particularly roundworms. You may even notice a worm in the vomit itself, resembling thin spaghetti. If you think your cat may have worms, call your vet for an official diagnosis and suitable treatment options, and always remember to stay up to date with your cat’s routine worming treatments.  

Clear liquid vomit in cats can also be a sign of the following: 

  • They are about to throw up a hairball 
  • They have drunk too much water 
  • They have eaten some grass or other plants 

If your cat is a wanderer, or you have houseplants in your home that your cat may have nibbled, call your vet. Many hopuse and garden plants are toxic to cats, even in small doses, and medical attention may be required.  

4. Vomiting White Foam in Cats

Cats vomiting white foam is another sign of vomiting on an empty stomach or from their oesophagus. The most common cause of this is your cat is hungry. Cats are creatures of routine, and their bodies are primed to remember mealtimes and are not afraid to remind you.

The white foamy liquid your cat vomits is usually a combination of stomach acids and saliva, which your cat’s body produces in anticipation of a meal. By ensuring dry cat food is available throughout the day, your cat can sate their hunger while awaiting their next meal.  

However, white foamy vomit may also indicate your cat is suffering from a health condition such as hepatic deficiency, diabetes, or hyperthyroidism, to name a few. Always err on the side of caution if you notice your cat vomiting white foam more than once and be mindful of other symptoms of these conditions, including:  

  • Weight loss 
  • Diarrhoea 
  • Increased thirst  
  • Jaundice  
  • Drooling 
  • Behavioural changes 
  • Lethargy 

If you notice any of the above as well as white foamy vomit, contact your vet for an official diagnosis.  

5. Cat Vomiting Undigested Food

When your cat vomits, you may be able to notice things in amongst any fluids that look like undigested food. This typically occurs very quickly after eating, and the most common cause is that your cat has eaten too quickly.  When eating, your cat will likely swallow a lot of air along with food, which causes stomach upset and then vomiting. If your cat eats too fast and then vomits after eating, the best course of action is to find what makes them eat so fast.  

Do they love to eat? Try serving them smaller meals throughout the day or using slow feeders or treat toys to enhance their meals. Having kibble readily available for them to nibble on can be a great help, too, but be wary, as this could lead to weight issues if they're continually eating too much. If they inhale their food to try and prevent any other pets in the home from eating it first, then try feeding pets separately in a place where they can feel safe and not rushed. 

Another reason your cat may vomit after eating is the food itself. If you change your cat’s diet too quickly without a transitional period, this can cause digestive problems that result in vomiting, among other things. This is why switching foods is recommended to be spread across 7-10 days, sometimes more, so your cat can get accustomed to the new diet.  

Your cat may even have an intolerance or allergy, causing it to regurgitate what it eats. In this case, there are likely other cat allergy symptoms present, such as:  

  • Itchy, inflamed skin 
  • Loss of fur or poor coat condition 
  • Sneezing or coughing 
  • Breathing difficulties such as wheezing

If you think your cat may be allergic to the ingredients in its current food, we recommend speaking with your vet to find the key allergen and choosing a new food that doesn’t contain it. You can also switch your cat to a hypoallergenic cat food that is formulated to exclude the most common allergens.  

6. Red in Cat Vomit

Unless your cat has eaten something red, any traces of red in their vomit are likely blood. The blood could be red or reddish brown. If the blood is noticeably red, it has likely come from its mouth, oesophagus, or stomach, which can be caused by your cat ingesting a sharp foreign object. In this case, you should call your vet as soon as possible, as this could be a sign of an emergency.  

The presence of any blood in your cat’s vomit is serious, and you should contact your vet as soon as possible.  

7. Coffee Ground Cat Vomit

If your cat's vomit looks like coffee grounds, you should contact your vet immediately after you’ve found the vomit.

The ‘Coffee Grounds’ in the vomit are actually partially digested blood that has likely come from your pet’s upper digestive tract. You may also notice their stools are black and tarry. This is a symptom of numerous gastrointestinal conditions, including, but not limited to:  

  • Cancers 
  • Ulcers 
  • Kidney disease 
  • Infections 

If there is ever blood in your cat’s vomit, red or otherwise, call your vet immediately and give them a description of both the vomit and your cat’s overall health and behaviour, including if they have been in any recent fights, suffered an injury, or have any existing health conditions. This will help them determine the issue's severity and advise you on what to do accordingly.  

8. Brown, Smelly Cat Vomit

If your cat’s vomit is brown and smells bad, it could be a sign that they’ve eaten something that fits that description, such as another animal’s faeces.  

However, it may also be a sign of bleeding in the upper gastrointestinal tract, the same as cat vomit, which looks like coffee grounds. Call your vet as soon as possible, and they can advise you on the right course of action.  

When To Call A Vet About Cat Vomiting

It’s important to remember that while vomiting in cats can be normal, it can also be a symptom of a larger issue that requires veterinary attention as soon as possible.

If your cat’s vomit has any sign of blood (black, brown, or bright red), contact your vet immediately.  

For the other kinds of cat vomit, monitor your cat closely and note any other symptoms or changes to your cat’s behaviour. If you have concerns, call your vet for further advice. While it could be normal, it is always best to err on the side of caution when it comes to your cat’s vomit, as they are species that tend to hide when they’re in pain or sick as a defence mechanism. For many conditions that cause vomiting, the sooner they are diagnosed and treated, the sooner your cat can be on the road to recovery.  

Remember, your vet is always there to offer you advice regarding your pet, and many will do so over the phone. If they do need to see your cat to assess their condition better, take them in as soon as possible.  

If your cat is healthy but suffers from occasional, mild digestive upset, introducing a probiotic supplement for cats could help soothe or prevent their symptoms. You can browse our complete range of cat digestion supplements below, including probiotics, hairball remedies, and more.  


This post is an opinion and should only be used as a guide. You should thoroughly discuss any change to your pet’s care or lifestyle with your vet before starting any program or treatment. 

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