Cat Farting (Flatulence) – Causes & Treatment

Causes    Diagnosis    Other symptoms  Treatment & prevention


At a glance

Farting is the passage of air from the gastrointestinal tract out of the anus.


As is expected, the most common causes are dietary and can include:

  • Lactose intolerance (from cow’s milk)
  • Swallowing too much air
  • Sudden change in diet
  • Fillers in food
  • Feeding table scraps
  • Malabsorption
  • Intestinal parasites


The goal is to find and treat the underlying cause.

cat farting

Also known as flatulence, farting refers to the expulsion of intestinal gases from the anus. All mammals pass gas, cats included. The smell comes from gases produced by bacteria within the stomach. A little farting is perfectly normal, if it is excessive, or becomes much more frequent then it may be time to look a possible cause.


Fillers in food

The most common reason for excessive flatulence in cats is diet related. Cheap, poor quality foods which contain high amounts of undigestible fillers (in the form of carbohydrates) are usually to blame. Switching to a high-quality diet will usually help.If you are already feeding a good quality food, then another possible cause is a food intolerance. This is different to food allergies, the immune system isn’t involved. One common intolerance is milk (see below).

Sudden changes in diet

Switching diets rapidly can be a problem. Cats are very sensitive to dietary changes. If you want to swap your cat from one type of food to another, do it gradually, over a few days. On day one mix 80% old food with 20% new food, day two 70% old food with 30% new food, and so on.

Swallowing air

Cats who eat too quickly are more prone to swallow large amounts of air can develop flatulence.

Table scraps

Many human foods don’t agree with cats and can lead to an upset tummy and flatulence. Table scraps should generally be avoided in any case, but if you must feed them, stick to bland types of food such as plain, cooked chicken. Don’t give your cat anything spicy or cured. It should go without saying that you should never feed your cat food that has passed its use-by date or has gone off. Cats can get sick just like humans if it’s not fit to eat, throw it in the bin.

Lactose intolerance

Most adult cats are lactose intolerant and this can bring about an upset tummy and cause excess gas. If you want to give your cat do so, but purchase the “cat milk” available at most supermarkets and pet stores.


Flatulence also occurs with malabsorption, a condition in which there is a deficiency in the digestive tract which results in food being poorly digested.  This is usually caused by an exocrine pancreatic deficiency (lack of pancreatic enzymes)  or inflammatory bowel disease.

Parasites (worms and giardia)

Parasites such as worms and giardia are common causes of flatulence. Giardia is a single-celled protozoan which causes severe stomach upset such as foul-smelling diarrhea and flatulence. Parasitic worms may cause no symptoms at all unless the infestation is heavy but are a known cause of flatulence in cats.


Your veterinarian will perform a physical examination of your cat and obtain a medical history, including questions about diet and nutrition and ask if any other symptoms have been observed. As we have already said, the most common cause of flatulence in cats is dietary related. If he suspects the cause isn’t dietary he may wish to perform some further tests including:

  • Blood tests to check the overall health of your cat.
  • Fecal tests to check for worms or giardia.
  • Specific tests such as fTLI (feline Trypsin-Like Immunoreactivity: This test measures the concentrations of trypsin-like proteins in serum. A low level indicates EPI.
  • Fecal proteolytic activity: Examination of the feces for fecal fat and fecal trypsin.
  • The only way to definitively diagnose inflammatory bowel disease is with a biopsy or histopathology of the intestinal tract and looking at the types of cells found under a microscope.

Other symptoms of flatulence

You may or may not notice if your cat has flatulence, but it may be accompanied by other symptoms that are easier to spot. These include:

  • Abdominal bloating
  • Abdominal pain
  • Vomiting
  • Diarrhea
  • Rumbling stomach

Treatment and prevention

  • Slowly switch your cat over to a high quality, low fibre diet. Add cooked pumpkin, butter or petroleum jelly to the food if you need to add fibre to help with hairballs. Cheaper brands of foods contain high levels of fillers such as corn, which are harder to digest.
  • Your cat only needs to drink water, which should be available 24/7. But if you must give him milk, make sure it is cat milk.
  • Avoid table scraps, cats don’t need them and many human foods can cause an upset tummy in cats as well as add excess calories to the diet.
  • If you suspect a food intolerance is a cause, slowly switch to another type of food. Unfortunately, it is not possible to test for food intolerances. Your veterinarian will recommend a trial diet which lasts between 8 – 12 weeks. Your cat will be put on a special diet, most often a type of food he’s never had before such as rabbit or duck to see if the flatulence (and other symptoms) clear up.
  • If your cat gulps down his food, feed several small meals a day instead of one or two large meals.
  • Regularly worm your cat to ensure he is parasite free.
  • Giardia can cause severe diarrhea and dehydration in cats. Seek veterinary attention if flatulence is accompanied by other symptoms such as diarrhea. Treatment of giardia is usually a course of antibiotics (most often Flagyl) or in some cases Fenbendazole, a medication to treat certain worm infestations.


Once you have ruled out common dietary causes such as cat food containing high levels of fillers, food intolerance, parasites then it is worth investigating if your cat is suffering from malabsorption disorder such as exocrine pancreatic deficiency or inflammatory bowel disease. Blood tests, fecal tests, and specialised tests will be necessary to diagnose the cause.


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