Bezoars in Cats

Causes, Treatment, and Prevention

A cat cleaning itself

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Bezoars are a common cause of belly aches in cats. Technically, these strange-sounding afflictions are hard masses of undigested material in the gut, but most are what we commonly call hairballs. While bezoars are often expelled by vomiting or passed in feces without causing harm. a bezoar that does not pass naturally may create a gastrointestinal obstruction. GI blockages require prompt veterinary treatment, or they can be fatal.

What Are Bezoars?

Bezoar (pronounced "BEE-zorr") describes a mass of foreign material that develops in the gastrointestinal tract, most often the stomach. The material usually forms into a firm ball up to an inch in diameter. Sometimes, an elongated mass forms that can measure up to five inches in length.

Symptoms of Bezoars in Cats

Bezoars that pass in vomit or feces may not cause symptoms other than mild discomfort or gagging in cats. However, those that are too large and compacted to be expelled can cause symptoms of gastrointestinal distress that will amplify if an obstruction occurs.


  • Loss of appetite
  • Retching/heaving
  • Vomiting
  • Diarrhea
  • Abdominal swelling
  • Restlessness
  • Vocalization
  • Lethargy
  • Weakness

Initially, a cat with a bezoar may not show any signs of illness. You may notice that your cat is retching or heaving in an attempt to vomit the stomach contents, but little or nothing comes up. If your cat has been coughing up hairballs frequently but suddenly loses interest in food or is not acting normal, then an impassable bezoar might need veterinary attention.

Causes of Bezoars

Hairballs are common in cats, but other bezoars are more likely to occur in other species, including humans, than in your feline friend.

  • Hair: Trichobezoars, commonly called hairballs, are comprised mainly of hair ingested while a cat grooms itself or another cat. The hair may be mixed with dirt and debris from the coat as well as food from the stomach. In small quantities, these materials may be able to pass through the GI tract or the cat may cough them up as hairballs. However, excess amounts of hair and debris may accumulate with food in the stomach and form a trichobezoar that cannot be passed.
  • Plants: Phytobezoars contain plant materials and fiber. Though uncommon in cats, if they do form, then they will often contain grass.
  • Pills: Pharmacobezoars are rare in cats. These occur when medications, especially antacids or enteric-coated pills, conglomerate to form a rock-like mass in the stomach. This happens when the coating or other ingredients in the pills become wet and stick together.

Diagnosing Bezoars in Cats

Bezoars are usually diagnosed based on the presence of expelled hairballs. In more complicated cases of possible gut obstruction, a veterinarian may be able to feel a mass when palpating your cat's abdomen. If a bezoar is suspected, then x-rays or an ultrasound may be used to assess the size, location, and type of blockage.


Some bezoars can be treated with oral laxatives and lubricating agents that help the cat more easily pass the mass. However, some bezoars are too large and hard to respond to these medications. In these cases, surgery may be required to remove the bezoar and any damaged tissue in the gut.

Prognosis for Cats with Bezoars

Most bezoars pass without too much trouble, but impassable bezoars can be life-threatening without surgery. Cats that are diagnosed and treated at the onset of symptoms have a much better chance of fully recovering.

How to Prevent Bezoars

The best way to prevent bezoars in cats is to minimize the amount of hair and debris your cat consumes. You can do this in the following ways:

  • Keep your cat well-hydrated by switching to a wet food diet and/or making water sources more appealing (cat water fountains appeal to some cats).
  • Add one-quarter teaspoon of olive oil or coconut oil to your cat's food daily during heavy shedding periods, if tolerated.
  • Brush your cat regularly or wipe its fur with a damp washcloth to reduce the amount of loose hair and debris.
If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.