Cat Throwing Up White Foam: What It Means and When to Worry

It can certainly be quite alarming to see your cat vomiting white foam, especially if you’re not sure what’s causing your cat’s puking. White foam in vomit is usually a mix of saliva and stomach acid, and it’s most common when the cat vomits on an empty stomach. The causes range from relatively harmless to dangerous, so it’s important to figure out the cause and take proper steps to help your cat get back to feeling well.

We’ll explain the reasons for a cat puking white foam, symptoms to watch for, and how your veterinarian will approach the problem.

What It Means When a Cat Throws Up White Foam

White foam in cat vomit is usually a mix of stomach juices and saliva. You may also notice mucus in the vomit.

Foamy vomit most commonly occurs when the cat’s stomach is empty, but it can occasionally precede or follow hairballs, non-food items that have been consumed, or partially digested food. Because the cat is usually vomiting on an empty stomach, the cat’s vomit may also have a yellow tinge. This color comes from the cat throwing up bile.

While one instance of a cat throwing up white foam may be harmless, frequent or severe vomiting is not normal. If your cat is vomiting multiple times in a day or vomits every few days, your veterinarian should be contacted. You should also speak with your veterinarian if you’re noticing other symptoms, such as decreased appetite or diarrhea.

Common Causes of White Foam Vomiting

Cats can vomit white foam for many reasons. Anything that could make them feel nauseous could make a cat vomit foam. Common causes of white foam vomiting include:

1. Empty stomach: Some cats vomit when their stomach is empty for long periods of time. It’s possible that the acid in their stomach irritates the stomach lining, causing them to puke. These cats may need to be fed smaller meals more often to prevent episodes of vomiting.

2. Hairballs: Foamy white vomit may come out before or after a hairball. While the occasional hairball isn’t surprising, especially in long-haired cats, excessive puking of hairballs could indicate an issue.

3. Dietary Indiscretion: If your cat eats something they shouldn’t, this may cause them to puke white foam. Strings, pieces of toys, houseplants, and food or medications intended for people are examples of foreign items that could cause vomiting white foam. These objects may directly irritate the gastrointestinal tract or cause a blockage, and some items, like lilies, are toxic to cats.

4. Food Allergies or Intolerances: While the most common sign in cats with food allergies is skin inflammation and itchiness, cats with allergies to specific foods may occasionally vomit white foam. Food allergies are usually triggered by the specific proteins, such as chicken or salmon, that are in the food.

5. Parasites or Infections: Parasites that affect the gastrointestinal tract, such as roundworms, stomach worms, or giardia, may cause a cat to vomit. Infectious diseases, like panleukopenia, can also cause vomiting white foam in cats.

6. Systemic Illnesses: Disease that affect organs outside of the stomach and intestines can cause vomiting. Examples include kidney disease, hyperthyroidism, pancreatitis, and liver disease. Foamy vomit is especially likely with systemic illnesses that also decrease appetite, such as kidney disease and liver disease.

7. Inflammatory Bowel Disease (IBD): Cats with IBD have an overreaction of the immune system in their intestines, causing a lot of inflammation. As a result, the lining of the intestines thickens, which affects the movement of food and absorption of nutrients in the intestines. Usually, the exact cause can’t be determined. Chronic vomiting is the most common sign of IBD in cats.

8. Cancer: In an older cat throwing up foam, cancer should be considered, especially if other more common systemic health issues are ruled out. Gastrointestinal lymphoma makes up over half of the cases of lymphoma in cats, and vomiting is a common sign of this cancer.

There are other cat vomiting causes. Your veterinarian will rule out the causes above before moving on to other rare causes of cat vomiting.

When to Worry: Signs to Call the Vet

If your cat vomits foam once but is otherwise acting normal and continues to have a good appetite, it’s usually okay to monitor them at home.

Signs that you need to call your cat’s veterinarian include:

• Vomiting multiple times in 24 hours
• Blood in the vomit or the stool
• Loss of appetite
• Lethargy
• Dehydration (dry gums, sunken eyes, decreased skin elasticity)
• Diarrhea
• Abdominal pain (hunched posture, reactivity to being picked up)
• Weight loss
• Excessive thirst and/or urination

You should always contact your veterinarian if your cat is vomiting after eating or chewing on something they shouldn’t, such as a string or houseplant.

Remember, frequent vomiting is never normal! If your cat pukes every few days, you should set an appointment with your veterinarian, even if they’re otherwise acting normal.

If your cat is vomiting or having diarrhea uncontrollably, is acting lethargic or uncomfortable, has pale or yellow gums, or collapses, this should be considered an emergency. Your cat should see a veterinarian as soon as possible.

Diagnosis and Veterinary Care

You can help your veterinarian reach a diagnosis by providing them with important information. Make sure to let your veterinarian know:

• Symptoms you’ve noticed and when they started
• If your cat’s diet has recently changed
• If your cat has eaten something they shouldn’t
• Any medications your cat is taking, including supplements and human medications

Your veterinarian will perform a full physical examination. This will include assessing your cat’s hydration and palpating (examining by touch) the abdomen for signs of pain, changes to internal organs, or the presence of foreign objects. Your cat’s history and the veterinarian’s physical exam will drive which diagnostics they recommend.

In a young kitten, your veterinarian is most likely going to start by ruling out infectious disease and gastrointestinal parasites. This will usually include testing a sample of feces. The sample will be examined under a microscope for the eggs of parasites. A swab test may also be used to detect giardia or panleukopenia.

An adult cat may still be tested for parasites, especially if they go outside or aren’t on preventatives. However, the veterinarian is more likely to focus on ruling out more chronic health issues, like kidney disease, IBD, or cancer. Testing will usually include:

• Blood work to assess the function of the liver, kidneys, pancreas, thyroid, and other organs, as well as rule out infection and anemia
• Urine testing, which can provide evidence of kidney function
• Imaging, most commonly abdominal X-rays and/or ultrasound of the abdomen

In some cases, more advanced diagnostics are needed, such as the collection of a surgical biopsy.

Treatment will depend on the results of diagnostics and physical exam. Common cat vomiting treatments include:

• Anti-nausea medications like maropitant
• Hairball gels or laxatives
• Dewormers, such as fenbendazole or pyrantel
• Fluids given through an IV catheter or under the skin
• Dietary changes, including prescription diets
• Pain medications like buprenorphine
• Medications for underlying illnesses, such as methimazole for hyperthyroidism
• Surgery for foreign body ingestion and some cancers
• Chemotherapy for cancers, like GI lymphoma
• Steroids for certain conditions, such as IBD

Cats with severe symptoms may need to be hospitalized for around-the-clock care.

If your cat is vomiting, you may be tempted to feed a bland diet, such as boiled rice and chicken. You should not feed a bland diet without veterinary guidance.

Home Care and Prevention Tips

Not all causes of a cat throwing up white foam are preventable. However, there are steps you can take to reduce your cat’s risk and to identify health issues before they’re serious.

1. Feed smaller, more frequent meals to avoid nausea from an empty stomach.
2. Maintain a consistent daily feeding schedule.
3. Make any dietary changes slowly over 7–10 days.
4. Do not give your cat human foods or medications.
5. Keep toxic houseplants out of the home.
6. Brush cats, especially long-haired cats, regularly to reduce hairballs.
7. Keep your cat’s vaccines up to date.
8. Give your cat monthly parasite preventatives.
9. Attend wellness visits as recommended by your veterinarian, making sure to budget for regular blood work to detect systemic health issues early.
10. Make sure you’re giving any prescription medications as directed by the veterinarian.

Always Check with Your Vet

While occasional vomiting may be mild and easily managed, frequent or severe vomiting requires a veterinary visit. Your veterinarian is your best resource for finding the cause of your cat puking white foam, and they can work with you to help your cat feel better. If your cat throws up white foam regularly or shows other symptoms, contact your veterinarian for diagnostics and a treatment plan.