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Why do My Cat’s Stools Smell so Bad?

Posted August 27, 2014 in Cat Diseases & Conditions A-Z

While stools do not normally have a pleasant smell, sometimes stools or feces can smell extremely strong and putrid. The cause for foul smelling stools in cats or humans can be very similar. It can be the food eaten, the bacteria in the colon1, and on occasion serious health problems. Additionally diarrhea and the presence of excess gas can cause bad odors.Cat on the floor

Many feline disorders are accompanied by diarrhea and foul smelling stools. In most cases, fortunately, the condition will be temporary, either self-resolving or readily remedied with a change of diet2. “In some instances, however,” according to Tom Ewing, of Cornell University’s College of Veterinary Medicine, “diarrhea can be a manifestation of a deeply rooted, possibly life-threatening condition.”

What causes smelly stool in cats?
In kittens, foul fecal odors are often associated with the introduction of new foods or with inflammation from parasites. In most cases, any fecal abnormality in an adult cat—if not clearly attributable to a dietary problem—is likely to be directly associated with the gastrointestinal tract and will most often be the result of an inflammatory or infectious disease or even cancer2. Your veterinarian will help you find the cause so appropriate treatment can be undertaken.

  • Diet as a cause of smelly stool in cats: Since people often vary their cats’ diet, it is sometimes difficult to determine what food ingredient is the offending agent. Sometimes an elimination diet (avoiding one ingredient at a time for a week or so), may help you narrow down the cause. Some cats are hunters and their prey can also cause smelly stools. Imagine your cat eating bugs, rodents and small reptiles and the smell may not be such a mystery—yummy! Surprisingly, vitamin supplements can also produce smelly stools. There are very few reasons to use vitamin and mineral supplementation in cats and today’s cat foods are well balanced so pet parents are more likely to cause problems by supplementing cat food. [Editor’s Note: Never add any sort of vitamin supplement to your cat’s food without talking to your veterinarian.]  
  • Bacteria as a cause of smelly stool in cats: Infectious enteritis may allow bacteria like E.coli or Samlonella to set up housekeeping. These organisms, as well as some viruses, can cause inflammation and result in diarrhea and gas that can be very foul smelling
  • Parasites as a cause of smelly stool in
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Mike has more than 35 years of experience in companion animal veterinary practice and is a valued member of IDEXX’s Pet Health Network team since 2013.