Causes of Vomiting & Diarrhea in Cats

For any pet owner, a vomiting cat or a cat with diarrhea is cause for concern. Since cats are vulnerable to a wide variety of different causes of an upset stomach, chances are, one or both has happened to your pet, but it’s often hard to know what to do. Do you rush them into the vet? Do you just let it pass?

Naturally, it depends. This article discusses the causes and symptoms of diarrhea and vomiting and cats, and discuss your options for home care, as well as when it’s time to take your sick cat into the veterinarian.

What is vomiting and diarrhea in cats?                               

Cat diarrhea (abnormally loose or liquid stools) and cat vomiting (the act of expelling content from the stomach through the mouth) is an unfortunate, but common part of pet ownership. In fact, they are the most common symptoms of upset stomach seen in cats.

Each fall under the term gastroenteritis, meaning an upset or inflamed stomach and intestines. Same as with people, diarrhea and vomiting can be caused by various underlying problems, ranging from minor to serious or even life-threatening.

Generally, vomiting points to irritation in the stomach and upper small intestine, and diarrhea indicates irritation anywhere along the intestinal tract. Vomiting and diarrhea can occur alone, or together and can be associated with an increased frequency of bowel movements.

But whenever either occurs, the underlying cause must be found and eliminated before it becomes a bigger problem. Chronic vomiting or diarrhea, meaning occurring regularly more than two to three times a week, can be a sign of a serious health issue.

What causes cat vomiting and cat diarrhea?

There are many possible causes for your cat’s vomiting and diarrhea. Theses can include overeating, eating something that they can’t digest, a change in your cat’s diet, infection and larger health issues. Most times, you will be able to trace the cause of your cat’s diarrhea or vomiting, but others can be more perplexing. Here are six of the possible causes.

Change in diet or food intolerance

If you recently changed your cat’s diet, he or she may experience some vomiting and diarrhea. Your cat may not be able to tolerate one (or more) of the ingredients in their new food, known as food intolerance. Cats may have intolerance to dairy products, wheat, corn, beer or other ingredients in their cat food.

To avoid this, you can try to gradually introduce the new food into their diet before you fully make the transition. This can help avoid negative reactions. You can also change back to their original food, or prepare a home diet to figure out what ingredient was causing the problem. Then you can re-start the process without the problem-causing ingredient. Your vet can help your form a transition diet, and sometimes a prescription diet may be required.

Some cats also may not be able to process commercially prepared foods as well as you’d like. These cats can often develop chronic diarrhea and vomiting, leaving them unable to properly absorb the nutrients they need from their food. This will cause low energy levels and deteriorate the quality of their coat.

Chronic diarrhea also correlates with inflammatory bowel disease, wherein the cat’s intestine becomes chronically inflamed and irritated. This will be extremely uncomfortable for your cat, and if left untreated, can also develop into lymphoma, a type of cancer in cats.

Eating something toxic

As naturally curious animals, cats are known to get into other things like the garbage and plants, or anything else they might find appealing. Sometimes, these items will contain toxic elements that cause the cat to throw up or have diarrhea. This is an acute form of poisoning, but can also be quite serious, depending what they consumed and how much.

There are several foods, plants and other items that are toxic to cats, but a few of the more common items include:

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


Gastritis or Enteritis

Gastritis and enteritis are conditions that can cause vomiting and diarrhea. Gastritis occurs when the stomach lining is inflamed, while enteritis refers to the irritation of the lining of a cat’s small intestine. When both of these conditions occur at the same time, it is called gastroenteritis. This condition can be caused by food, viruses, parasites, bacteria or fungi.

Intestinal Parasites

Parasites and worms in the intestines can cause stomach irritation, making a cat likely to vomit and have diarrhea. When this is the cause, there will be worms or pieces of worms visible in your cat’s feces.

Tapeworms, hookworms, roundworms, coccidia or giardia are known to often infect cats. Your vet can help you eradicate the worms through medication and fluid therapy may assist if your cat is severely dehydrated.

Various bacteria, fungi and infections

There are many forms of bacteria, viruses and fungi that can be the primary cause of your cat’s vomiting and diarrhea. The most well-known bacteria that causes cat vomiting and diarrhea is Salmonella, which is found in infected meats and food. Cats also frequently get yeast infections, caused by fungi. When the yeast infection affects the intestines, your cat will have watery stools and may vomit as well.

Heat stroke

Since they are covered in fur, cats lack an efficient way to cool themselves down. Cats eliminate heat through their paws. If the temperature is too high, your cat can often have a heat stroke.

Cats will often vomit or have diarrhea if they are having a heat stroke, but in worse cases, they will have seizures or go into a coma. If the symptoms are minor, try to cool your cat down with cold compr