Why is My Cat Vomiting? Causes and Treatments

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Learn about why cats vomit food, hairballs, grass, and so forth. Learn about when you need to take a cat to a veterinarian if they are vomiting, or throwing up. Treatments for cats who throw up are also covered. Why do cats vomit? Why is my cat vomiti

Cats vomit for several reasons, it is important to know that all cat vomit is not the same, sometimes it is food related, other times hairballs, but can also be a sign of a health concern or emergency that requires veterinary attention.

Cat Vomit Types

  • A hairball is typically one solid piece, it may look like a mouse. If the cat goes outside it may have some grass in it. Often liquid bile is regurgitated along with the hairball.
  • Food vomit often looks like food, and falls apart easily. There may or may not be bile with it.
  • Other times cats simply vomit bile, a yellow liquid, they may also vomit grass at this time.
  • In cases where the cat has a heavy infestation of worms, they can even vomit worms.


Hairballs develop when cats groom themselves and swallow excessive amounts of hair. If too much hair accumulates in the cats stomach it blocks the flow of digestion, as such cats vomit these large blobs of fur out of their system. Brushing will reduce some of the loose hair but feeding a better quality cat food will also lower the occurrence of hairballs because it will improve the health of the cats skin, coat, and digestive system. You may note that there are many “Hairball” formula foods that only deal with digestion, and are low quality so do not otherwise reduce shedding.

Food Vomit

Food vomit can occur for many reasons, the cat eats too fast, eats too much, or the food is hard on the cats stomach and it responds by vomiting. This is more often a problem with dry food – although cats will vomit up rotten canned food (typically they wont eat rotten food). With many low quality dry cat foods the manufacturer adds fat to give the food flavor. These foods typically contain very little meat, and since cats are carnivores they must eat a lot of the poor quality food to get any nutrition, thus they eat more fat. Fat is hard on their stomachs, and they vomit in response.

Cat foods that contain a lot of color dyes may result in similar problems when a cat is sensitive to food color allergies. Foods that contain mystery meat, (meat meal) which can be any dead animal, often result in vomiting due to allergies and the fact that the ingredients are not consistent from bag to bag.

When owners make a food change too suddenly this too can result in food vomit.

Some cats have allergies to ingredients in cat food, beef being one of the more problem ingredients, where as chicken and lamb are often considered more gentle on a cats tummy. Food allergies also result in cats having itchy skin, and diarrhea.

Food vomit can also occur when a cat is eating a food that is too rich for its stomach, as when a senior cat might eat kitten food.

outdoor cat in the grass

What is with the Grass in a Cats Vomit?

Cats instinctively chew on grass, or sometimes house plants, to encourage themselves to vomit. This is usually not a problem, unless the home owner has treated the plants with pesticides. If this type of vomiting occurs frequently (more than once a week) the cat owner should consider taking their pet to the veterinarian for a health check up.

When to take a Vomiting Cat to the Veterinarian

Cats with roundworms may vomit them up. It is important to note that if this happens the cat should be taken to a veterinarian for the proper deworming as they may still have other worms in their system.

Cats that vomit blood need veterinarian attention.

Cats that vomit every few days, and not always right after eating (which would indicate a problem with the food) may have a health concern such as diabetes, irritable bowel syndrome, worms, liver disease, or any number of other problems, and should see a veterinarian. This is urgent if they seem to be losing weight.

Cats that keep trying to vomit. If the cat has already thrown up and seems to be retching for a long time afterwards it may have a blockage, or even ingested poison, and should see a veterinarian immediately.

If the cat throws up foul looking matter that resembles feces it may have an intestinal blockage and should see a veterinarian immediately.

Projectile vomit is also a call to see the veterinarian immediately.

If you have recently treated the cat with a flea remedy your cat could be having an allergic reaction to the chemicals used. Over the counter flea remedies have killed many cats and dogs and should be of immediate concern. See the link below to learn more before it happens to your cat.

Some things to Note

  • If your cat goes outside it may be at risk for ingesting a poison.
  • If your cat is not vaccinated it is more likely to get sick.
  • If your cat has other symptoms it should most definitely see a veterinarian.

Treatments for Hairball Vomit Problems

The cat should be brushed more frequently, stress should be reduced (as stress leads to increased shedding).  The cat should be on a better food (one that does not have corn as a main ingredient).  Feeding canned pumpkin may also improve the situation but is not a long time fix.

Treatments for Food Vomit Problems

If the vomiting is food related (and therefore does not require veterinarian attention) the best course of action is to remove food for half a day, and slowly reintroduce the food, but at this time look into switching the cat over to a more healthy food (one with chicken, or lamb, as a first ingredients, and contains no by-products, meat meal, ethoxyquin, color dyes, or other problem ingredients). Switch by mixing the new food with the old, and at first offer small portions.

Related Reading

Why does my cat have Diarrhea?

Is the Food your Cat Likes Good Food for you Cat?

Ethoxyquin – the Deadly Ingredient in some Pet Foods

Is your Pets Flea Medication Killing your Pet?


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