Hairball
毛玉 (kedama)
Definition
A clump of swallowed fur that forms in a cat's stomach during grooming and is typically brought back up or passed in stool; the same thing can happen in dogs, though it is talked about far more with cats.
Key points
- Hairballs form when a cat swallows loose fur during grooming and it clumps in the stomach instead of passing through
- Occasional vomiting of a hairball is common in cats and is not on its own a sign of illness
- More frequent brushing and a fiber-forward food are the two changes most often suggested
- Repeated retching without producing a hairball, or a drop in appetite, is a reason to call the vet
What is a hairball in cats?
A hairball is a clump of fur that a cat has swallowed while grooming, which has gathered together in the stomach instead of passing all the way through. Dogs can bring one up too, but the topic comes up far more with cats, since grooming is such a frequent part of their day.
Most swallowed fur simply travels through and shows up in stool. What does not pass sometimes clumps and is brought back up, usually as a damp, tube-shaped wad rather than a neat ball.
Where it fits in gut care
How much fur a cat swallows, and how easily it moves through, both play a part here. A cat that grooms often, or carries a long coat, naturally takes in more fur during shedding season. Once that fur reaches the stomach, whether it clumps or keeps moving depends in part on the same things that shape dietary fiber intake and hydration: enough moisture and enough fiber to help material move along rather than sit still.
What owners can do
Brushing more often is the change most cats notice fastest, since it removes loose fur before it can be swallowed at all. During shedding season, daily brushing is often suggested rather than the usual weekly pass.
A few other things owners commonly try:
- A food built around insoluble fiber, introduced gradually as part of a normal food transition rather than swapped overnight
- More water intake, through a fountain, extra bowls, or wet food, since dehydration can make it harder for swallowed fur to move along
- Keeping an eye on stool, since a change there can be an early sign that something is not moving through as expected
Occasional hairballs are not a reason for alarm on their own. Repeated retching that does not produce anything, a loss of appetite, or a belly that seems swollen or painful are different, and are reasons to have your cat examined rather than continuing to watch and wait.
This entry shares general knowledge and is not veterinary advice. It is not intended to diagnose, treat or prevent any condition. If you have concerns about your dog or cat, please consult your veterinarian.
FAQFrequently asked questions
Why does my cat throw up hairballs?
Cats swallow loose fur every time they groom, and most of it passes through in stool. Whatever does not pass sometimes clumps together in the stomach and comes back up as a hairball. Occasional hairballs are generally considered normal, especially in cats that groom often or carry a longer coat.
How can I prevent cat hairballs?
Brushing more often is usually the first change suggested, since it removes loose fur before your cat has a chance to swallow it. A food built around fiber is another common approach, though how well it works varies from cat to cat.
Is a hairball diet effective for cats?
Diets built around fiber are designed to help swallowed fur move through the digestive tract rather than sit in the stomach. Results vary by cat, and diet is generally treated as one part of a plan that also includes brushing and enough water intake.
When is a hairball a reason to see the vet?
Repeated retching that does not produce a hairball, a drop in appetite, or a swollen or painful abdomen can point to a blockage rather than an ordinary hairball, and are reasons to have your cat seen rather than waiting it out.