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If you own a cat, you have likely cleaned up a puddle or two of vomit. Cats vomit for many reasons that usually are benign, but some vomiting cases can indicate a serious health condition. The following article provides information about vomiting causes in cats to help you determine if you should be concerned the next time your cat is sick on your carpet.

What causes vomiting in cats?

Vomiting is the active evacuation of stomach contents, and conditions that can cause your cat to vomit include:

• Hairballs — Cats swallow hair when they groom themselves and periodically vomit hairballs, which appear as a damp, cylindrical wad of undigested hair. Most cats expel a hairball about once every one to two weeks.

• Dietary indiscretion — Any sudden change in your cat’s diet can lead to vomiting.

• Foreign body ingestion — Ingesting a foreign body can lead to a gastrointestinal (GI) obstruction that may cause vomiting or retching.

• Parasites — Intestinal parasites may cause your cat to vomit.

• Food allergies — Cats may be allergic to ingredients in their food, resulting in vomiting. Most cats with food allergies also have itchy, inflamed skin.

• Inflammatory bowel disease (IBD) — Inflammation in your cat’s stomach, small intestine, and large intestine can cause vomiting.

• Cancer — Lymphoma is the most common form of cancer in cats, and signs include vomiting, weight loss, and diarrhea.

• Toxin ingestion — Certain toxins, including ibuprofen, ethylene glycol, and insecticides, cause vomiting in cats if ingested.

• Kidney disease — If your cat’s kidneys aren’t working properly, toxins build up in their bloodstream and can cause vomiting.

• Diabetes — Diabetic cats can develop ketoacidosis, resulting in vomiting.

• Feline infectious peritonitis (FIP) — FIP is a viral infection that can affect many organ systems and may cause vomiting.

• Liver disease — Liver disease allows toxin buildup in the cat’s bloodstream, which can lead to vomiting.
• Neurological conditions — Neurological conditions can interfere with the part of the cat’s brain that triggers nausea and can cause vomiting.

What does the vomit’s appearance mean about the cat’s condition?

The color and consistency of your cat’s vomit can help determine the cause of the problem. Always ensure you note the vomit’s appearance so you can relay the information to your veterinarian. Examples include:

• Clear — Vomiting water may mean your cat drank too much water, and may indicate a condition, such as kidney disease or diabetes, that leads to increased thirst.

• Food — Cats who eat too much or too fast can vomit food. This may also occur if they have a food allergy.

• Green — Green vomit usually means the GI contents came from the small intestine and are mixed with bile.

• Mucus — Mucus on your cat’s stomach contents typically means they have regurgitated, rather than vomited. Regurgitation is a passive expulsion of the stomach contents, and differentiating between regurgitation and vomiting is important when diagnosing the problem.

• Red — Vomit can be bloody if your cat has esophageal or stomach ulcerations, and can also occur if they have a clotting abnormality. You should seek veterinary attention if your cat is vomiting blood.

• White foam — White foam usually indicates your cat’s stomach and small intestine are inflamed.

• Worms — Parasites such as roundworms can sometimes be found in your cat’s vomit.
• Yellow — Yellow vomit, which indicates your cat has an empty stomach, can occur if you feed your cat only once a day, or if they stop eating. Food stimulates gallbladder contraction, and when no contractions occur, bile can back up into the small intestine and stomach and cause your cat to vomit.

Should I be concerned if my cat vomits?

Cats vomit quite readily, and an occasional episode in an otherwise healthy cat is not cause for concern. Situations that indicate veterinary care is needed include:

• You have a kitten or senior cat.
• Your cat vomits repeatedly.
• Your cat exhibits other signs, such as lethargy, fever, dehydration, inappetence, abdominal pain, and diarrhea.
• Your cat does not eat or drink for 12 hours.
• You know or suspect your cat ingested a foreign body.
• You know or suspect your cat ingested a toxin.
• Your cat has been diagnosed with an illness such as diabetes, kidney disease, or hyperthyroidism.
• Your cat vomits blood.
• Your cat vomits a worm, which indicates they need deworming medication to clear the parasites.

How will my veterinarian determine why my cat is vomiting?

In cases where vomiting is concerning, diagnostics to determine the cause include:

• Blood work — A complete blood count (CBC) and biochemistry profile are helpful to assess your cat’s overall health status and rule out conditions such as kidney disease, liver disease, and diabetes.

• X-rays — X-rays can reveal issues such as foreign bodies and GI tumors.

• Ultrasound — Ultrasound can help visualize foreign bodies that cannot be seen on X-rays and inflammation in the stomach and intestinal lining.

• Endoscopy — An endoscope (i.e., a flexible tube with a camera on the end) can be inserted in your cat’s mouth to visualize their stomach, looking for ulcerations, and to take biopsy samples for further testing. This procedure requires general anesthesia.
• Exploratory surgery — In some cases, exploratory surgery is necessary to determine what is causing the vomiting.

How is vomiting treated in cats?

The underlying cause should be treated to remedy vomiting, but in mild cases, non-specific, symptomatic treatment may be prescribed that involves:

• Withholding food and water — Withhold food and water for several hours to let your cat’s GI system rest and calm down.
• Feeding a bland diet — After a few hours, offer your cat a small amount of a bland diet. A veterinary prescription diet specifically formulated for easy digestion is often recommended. 
• Going slowly — Gradually increase the amount you feed your cat over the next 48 hours, and ensure they have free access to fresh, clean water.
• Providing medication — Your veterinarian may prescribe medication to control vomiting or decrease inflammation.

In most cases, cat vomiting is not concerning, but this information should help you know what to do the next time your cat has an episode.