Causes of Cat Vomiting and Diarrhea

Cat vomiting and diarrhea are symptoms that often occur at the same time, indicating food intolerance that can go away on its own, or more severe illnesses that need medication. Isolated episodes of cat vomiting and diarrhea are normal. However, if the condition is chronic or lasts for more than 48 hours, a vet must be notified.

Gastritis or Enteritis

Gastritis occurs when the stomach lining is inflamed; enteritis indicates the irritation of the small intestine lining. These conditions cause vomiting and diarrhea. When both conditions occur, the cat has gastroenteritis.

Gastritis and enteritis can be caused by food, viruses, parasites, bacteria or fungi.

Upset Stomach

An upset stomach might indicate food intolerance. This is different than food allergies. Food intolerance manifests itself with the cat vomiting and having diarrhea, while allergies will display rashes and itchiness.

It is important to identify the ingredient that causes the intolerance and make sure you avoid it. Cats can be intolerant to dairy products, wheat, corn, beef or other food ingredients. In some cases, a prescription diet will be needed.  

Intestinal Parasites

Intestinal parasites and worms can cause stomach irritation, and the cat is likely to vomit and have diarrhea. There might be worms or worm segments visible in the feces. Cats often get infected with tapeworms, hookworms, roundworms, coccidia or Giardia.

The uneasiness can be relieved with dewormers and possibly fluid therapy, if the dehydration is severe.

Various Infections

Bacteria, viruses and fungi could be the primary cause of your cat's vomiting and diarrhea.

Bacteria that can cause vomiting and diarrhea include Salmonella, which can be found in infected meats and food, or Clostridium perfringens.

Yeast infections are caused by fungi and can be frequent in cats. If the yeast infects the intestines of the cat, he will throw up and have watery stools.

Sudden Change in Diet

If you have recently changed the type of diet for your pet, he may react by vomiting and having diarrhea. Try to make the transition gradual to avoid negative reactions. Talk to your vet about a transition diet.


Cats are curious animals and besides the cat food, they like to try different other “foods” such as garbage, plants or other appealing objects. Some of these may contain toxic elements for cats. Pets will throw up and have diarrhea as a result of poisoning.

Some common toxic foods, plants and other items include:

  • Alcohol
  • Chocolate
  • Raisins
  • Chewing gum containing xylitol
  • Rat poison
  • Aloe vera plant
  • Raw plants from the potato family

Heat Stroke

Cats don’t have an efficient way to cool themselves down. They eliminate heat through the paws and if the temperatures are too high, the cat can suffer from a heat stroke. Vomiting and diarrhea are symptoms of a heat stroke. In more advanced stages, the cat will have seizures or coma.

Try to cool your cat down with cold compresses.

More serious causes of cat vomiting and diarrhea include diabetes, tumors located in the intestine or stomach, stomach ulcers or liver disease.

A cat that is vomiting and has diarrhea can get dehydrated. Provide fresh water, or in more severe cases, get fluid therapy to prevent dehydration.

Visit your vet if the cat displays the symptoms for more than 2 days or if there is blood in the vomit or stool.