Why Your Cat is Throwing Up and What To Do

Cathy Meeks, MS, DVM, DACVIM
By Cathy Meeks, MS, DVM, DACVIM on Jan. 28, 2021
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In cats, it can be difficult to tell the difference between retching/vomiting, regurgitation, and coughing. These are all very different and come with different possible causes, so it is important to try and differentiate between them.

Vomiting is the active motion of ejecting contents from a cat’s stomach and small intestines out through their mouth. This is different than regurgitation, which is a passive motion where no force is needed to eject contents through the cat’s mouth. You might also mistake these for coughing if you didn’t witness anything coming out.

The best thing to do is to take a video, if possible, to show your veterinarian. They can help you determine whether it really is vomiting, and if so, why your cat is throwing up. Here’s some helpful information on cat vomiting causes and possible treatments.

Why Is My Cat Throwing Up?

Your veterinarian will ask a variety of questions to determine why your cat is vomiting. These include:

  • Have you switched your cat’s diet recently?

  • Have you started any prescribed or over-the-counter medications?

  • What diet, including all treats, is your cat on?

  • Do you have other cats in the house, and if so, are they also vomiting?

  • Is your cat indoor and/or outdoor?

  • How often is your cat vomiting, and what does the vomit look like?

  • Is your cat still eating?

  • Is your cat having other symptoms, such as diarrhea and/or weight loss?

  • How long has your cat been vomiting?

There are several possible causes of cat vomiting, and these questions will help guide your veterinarian in the right direction. Possible reasons why cats throw up can be broken into two categories—gastrointestinal causes and non-gastrointestinal causes.

Gastrointestinal Causes of Cat Vomiting

Non-Gastrointestinal Causes of Cat Vomiting

What Does Your Cat’s Vomit Look Like?

Knowing what your cat’s vomit looks like is very important, as different diseases can cause the vomit to have a more distinct appearance. Here are some examples of vomit color/consistency and possible causes for each.

Bile/Yellow

Cats will vomit bile when they have an empty stomach. This can happen if you are only feeding your cat in the morning and they go 24 hours without food, or it can happen when cats are anorexic. Food stimulates the gall bladder to contract, but when the gall bladder does not contract, the bile can back up into the small intestines and stomach.

Blood

Blood can be seen with ulcerations, or if your cat vomits several times in a row, this can cause an irritation of the stomach lining and esophagus because of the increased acid. Blood can also be present if there is a clotting abnormality, which can be seen with certain diseases and some toxins (rat poisoning, for example).

White Foam

White foam in cat vomit is oftentimes seen because the lining of the stomach and/or small intestines is inflamed from many possible causes.

Water/Clear Liquid

If your cat is vomiting clear liquid, it can be the fluid contents of the stomach, or your cat might have drunk too much water. There are many possible diseases that can cause cats to drink too much water, including diabetes mellitus and kidney disease.

Worms

The most common type of worm seen in cat vomit is roundworms. If your cat vomits a worm, it is important to bring this to your veterinarian so they can treat the issue appropriately.

Food

Cats who eat too much or too fast can vomit food, and it typically it appears in a tubular shape.  They can also vomit food if they become nauseous shortly after eating, if there is a foreign body obstructing the food from moving into the small intestines, or if they have a food allergy.

Hairballs

Cats can occasionally vomit hairballs, especially cats who overgroom or cats with long hair.

Brown Liquid

This is usually indicative of digested blood further down the intestinal tract and can be seen with ulcerations, foreign bodies, or even hairballs in the intestines.

Green Vomit

If your cat is throwing up green vomit, this usually indicates that the food or substance was brought up from the small intestines. The mixture of the vomitus with bile can turn the color green.

Mucus

Mucus is typically seen if your cat is regurgitating and not vomiting. If you see mucus, it is very important to determine if your cat is actually vomiting or if they are regurgitating.

Cat Vomiting With Other Symptoms

Oftentimes when cats do vomit, they have other symptoms, too. Describing all of your cat’s symptoms to your veterinarian will be important in determining the right diagnostics or treatments.

Your cat is vomiting and not eating. 

It is very common for cats to not want to eat if they are nauseous. You can see this with a variety of conditions, including foreign bodies, kidney and liver disease, severe diabetes, inflammatory bowel disease, etc.

Your cat is vomiting and constipated.

If your cat hasn’t defecated in a couple of days and is straining to go, they are likely constipated. This can cause a backup of contents in the small intestines and stomach, causing cats to vomit.

Your cat is vomiting and having diarrhea.

This combination of symptoms tells us that there is not only inflammation within the stomach but also within the small and/or large intestines.

Your cat is vomiting and sneezing.

If your cat has acute vomiting and sneezing, they could have contracted a virus (such as coronavirus). It is not uncommon for cats who become sick (vomiting) to also develop an upper respiratory tract infection. This is because a large portion of cats contract certain viruses, such as herpesvirus, as kittens, and can be acting normal until they are immunocompromised.

Your cat is vomiting and drinking a lot.

Cats can vomit after they drink a large amount of water. They can also have disease that cause them to drink a lot and have vomiting, such as kidney disease, diabetes mellitus, and cancer.

Your cat is vomiting and pooping on the floor.

Cats may defecate on the floor if they have constipation or have an increased urgency to go, which can be seen with intestinal inflammation and diarrhea.

Should I Call the Vet if My Cat Throws Up?

You should call your veterinarian right away if:

  • Your cat vomits more than two to three times in a row.

  • Your cat has other symptoms, such as not eating and diarrhea. If your cat is also having diarrhea, it will be difficult to keep them hydrated without seeing your veterinarian.

  • Your cat does not eat or drink for 12 hours and has vomited several times in a row.

  • Your cat has already been diagnosed with an illnesses (such as diabetes, kidney disease, and hyperthyroidism). This is an emergency, and your cat should be seen immediately, as this could mean that their disease is progressing. Early medical intervention is necessary in these patients, as they can become dehydrated very quickly.

  • Your cat has vomited a worm. You need to deworm your cat and any other animals in the household as soon as possible. It is also important to keep the environment clean and scoop the litter boxes several times a day to ensure that your pets do not get reinfected.

Can I Give My Cat Anything at Home for Vomiting?

Unfortunately, there are not many over-the-counter medications that will help cats not vomit. If your cat does start to vomit, do not give them anything by mouth (including water or food) for several hours.

When Can I Feed My Cat Again After They’ve Thrown Up?

After waiting several hours, you can try to give your cat about 25% of what you would normally feed to see if they can keep it down. Then gradually increase the amount over the next 24 hours. If your cat starts vomiting again, you will need to seek veterinary help.

How Vets Treat Cat Vomiting

It’s important to distinguish between acute vomiting and chronic vomiting. Chronic vomiting is defined as a cat who vomits more than once a week or has been vomiting on and off for more than three months. This is much different than a cat who suddenly starts to throw up (acute).

Treating Acute Vomiting in Cats

The first step in properly treating your cat for vomiting is identifying the underlying cause. First, your veterinarian will do noninvasive diagnostics. This includes:

  • A chemistry and CBC (general blood tests) to screen for diseases such as kidney disease and diabetes.

  • A fecal exam to rule out parasites.

  • Abdominal radiographs to rule out larger tumors or foreign bodies that might be causing an obstruction. 

If these tests are normal, and your cat is acutely vomiting, your veterinarian will likely recommend supportive treatments with anti-nausea medications. 

Cats that vomit from hairballs can be placed on a special high-fiber diet along with a medication to help ease the passage of hairballs.

Treating a Cat That Keeps Throwing Up (Chronic Vomiting in Cats)

If your cat continues to vomit or has a history of chronic vomiting, further testing would be indicated as described below:

  • Gastrointestinal panel: This will test the pancreas enzymes to rule out pancreatitis. It will also look at cobalamin and folate to determine if there is evidence of malabsorption in the small intestines.

  • Abdominal ultrasound: This imaging modality is very sensitive at identifying smaller foreign objects that x-rays cannot. This ultrasound looks at the pancreas and helps measure the wall of the gastrointestinal tract. It will also help rule out any enlarged lymph nodes that can sometimes be seen with cancer.

  • Chest x-rays: These may be recommended if it is not clear whether your cat is vomiting, regurgitating, or coughing. Chest x-rays are also recommended in older cats to rule out evidence of cancer.

In some cases, the diagnostics come back normal or do not provide a definitive diagnosis. This can be seen if the disease is at the cellular level of the small intestines. 

In this instance, the next step would be obtaining biopsies of your cat’s gastrointestinal tract to differentiate between inflammatory bowel disease, food hypersensitivity, and gastrointestinal lymphoma. Your veterinarian may try a new diet prior to obtaining biopsies in the event that this is related to a food allergy.

Featured image: iStock.com/krblokhin

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Cathy Meeks, MS, DVM, DACVIM

WRITTEN BY

Cathy Meeks, MS, DVM, DACVIM

Veterinarian

Dr. Cathy Meeks started her veterinary career as a veterinary technician while getting her Master's degree in Veterinary Medicine, Forensic...


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