When your cat hacks up a slimy fur sausage of a hairball, you may be disgusted or annoyed (especially if you're bare foot or a favorite rug is involved). You may also wonder whether that’s normal. An occasional regurgitated wad of hair isn’t cause for alarm, but frequent hairballs might mean your cat has an underlying health problem, such as anxiety, allergies, or an imbalanced gut microbiome (the community of bacteria in the digestive tract).
What Causes Hairballs?
Domestic cats spend 30%–50% of their day grooming themselves. It’s a healthy activity; grooming is how cats stay clean, but it’s also soothing. Because of the hook-shaped protrusions (papillae) on their tongues, they end up swallowing a lot of the loose hair they lick out of their coats. Hair is made of keratin, a protein mammals can’t digest, so most of the fur cats swallow is passed along, unprocessed, and eliminated with the stool.
(When cat parents send poop samples to AnimalBiome for gut microbiome analysis, they’re sometimes alarmed at seeing clumps of hair in their cats’ stool. But that’s actually normal. AnimalBiome has processed thousands of samples of cat poop, and according to Chief Science Officer, Holly Ganz, “I can tell you that there is a lot of hair in there.”)
But some of the ingested hair can remain in the stomach and form a ball—the technical term is a trichobezoar. If this hair wad is too big to pass into the intestines, it’s regurgitated instead. (Traveling through the esophagus on its way back out squeezes the ball into more of a bullet or sausage shape.)
Hairballs happen either because the ingested hair can’t move easily through the cat’s digestive tract or because the cat is taking in too much hair for the digestive system to handle. (What about dogs? It’s rare for dogs to have hairballs, but it does happen.)
How Many Hairballs Are Normal for a Cat?
As to how many disgorged hairballs qualify as “normal,” the number varies somewhat among veterinary authorities. Some say a healthy cat might vomit up a wad of fur every week or two. Dr. Brunt says even long-haired breeds, like Persians and Maine Coons, “should not develop more than one or two hairballs a year.”
But all the feline experts agree that excessive production of hairballs can point to an underlying health problem.
Hairballs and Your Cat’s Gut Microbiome
Frequent hairballs may be a sign that the digestive system’s ability to move material along—its motility—is impaired. Reduced motility means that food and moisture don’t progress through the intestines the way they should, and digestion suffers. But another important aspect of proper motility is that it limits the amount of time that pathogens and antigens are in contact with the intestinal walls. When these substances aren’t properly cleared away from the lining of the gut, the resulting bacterial overgrowth can interfere with the body’s absorption of nutrients.
When a cat’s gut bacteria populations are out of proportion or key beneficial bacteria are missing, we describe the gut microbiome as imbalanced. An imbalanced gut microbiome is one of the factors that can lead to inflammatory bowel disease (IBD), and chronic inflammation of the digestive tract can severely disrupt motility.
If you want to learn more about your own cat’s gut health, order our at-home KittyBiome Gut Health Test. You’ll receive a personalized report that includes actionable insights, with diet and nutrition recommendations based on your cat’s unique microbiome composition. Because microbiome testing can identify problematic groups of bacteria and detect imbalances early, you may actually be able to prevent certain health problems in your feline by making changes in their diet.
Do big cats get hairballs? Even though big cats—like lions and leopards—groom themselves the same way house cats do and have the same bristly tongues, they almost never get hairballs. On the other hand, hyenas, a cousin of the cats, are able to digest bones but not hair, and solve this problem by regularly regurgitating hairballs in the wild.
Overgrooming May Indicate Anxiety or Allergies
Cats who barf up a lot of hairballs may be ingesting an abnormal amount of hair because they’re grooming too much. Obsessive grooming can be a sign of anxiety—in response to a sudden change in the cat’s environment, for example—but it may also point to allergies, food sensitivities, or skin conditions that cause itching. Cats may also react with aggressive licking when a part of their body is in pain. So if you think your cat is grooming too much or too vigorously, check in with your veterinarian.
Can Hairballs Be Dangerous?
If a hairball gets stuck somewhere in the digestive tract, the resulting blockage can be life-threatening. Intestinal blockages require prompt surgical intervention, so if your cat has any of these symptoms of a possible blockage, see your veterinarian immediately:
repeated unproductive retching
lack of appetite
(Coughing is sometimes misinterpreted as hairball-related hacking. Coughing may indicate asthma or other respiratory issues, so it’s important to consult your veterinarian if your cat has a cough.)
What Can You Do to Prevent Hairballs?
Daily brushing helps remove loose hair and is especially helpful for long-haired cats.
Feeding multiple small meals rather than one or two big meals per day can help prevent hair from building up in the GI tract.
Don’t give your cat any sort of laxative without first consulting your veterinarian.