A hairball is exactly what it sounds like: a wad of swallowed fur, bound together with stomach mucus, that the cat coughs up because it didn't move through to the gut. The technical name is a trichobezoar. They're common, mostly harmless in small numbers, and almost entirely preventable.
Why cats get them
Cats groom by licking, and the tongue has small backward-facing barbs that pull loose fur into the mouth. Most of that fur passes through and ends up in the litter box. Some of it doesn't — it builds up in the stomach until the cat brings it back up.
Hairballs are more common in:
- Long-haired breeds (Maine Coons, Persians, ragdolls).
- Cats during spring and autumn coat changes.
- Older cats, who groom more and have slower gut motility.
- Cats with skin conditions or fleas that cause over-grooming.
One or two hairballs a month is unremarkable. More than that is worth addressing.
Prevention that actually works
The single biggest lever is brushing. Less fur in the cat means less fur in the stomach.
- Short-haired cats: five minutes, two or three times a week.
- Long-haired cats: ten minutes, daily during shedding seasons; every other day otherwise.
Use a slicker brush for the topcoat and a fine metal comb to catch the undercoat. A grooming glove is a gentler intro for cats who hate brushes; once they tolerate the glove, you can usually switch.
Diet and fibre
A small amount of dietary fibre helps move ingested fur through to the stool instead of letting it accumulate. Options, in rough order of ease:
- A hairball-formula dry food. These are higher in fibre. Effective for most cats; not a fix on its own if you're not also brushing.
- A teaspoon of plain pumpkin (not pie filling) stirred into wet food, two or three times a week.
- A hairball gel (Laxatone, Petromalt) given by mouth once or twice a week. The malt-flavoured ones go down easily.
Skip the homemade oil remedies. Mineral oil in particular can be aspirated and cause pneumonia.
Water matters too. A well-hydrated cat passes fur more easily. If your cat doesn't drink much, see cat water intake for ways to lift it.
When a hairball isn't a hairball
The retching motion that produces a hairball looks the same as the retching that produces other things. If you're seeing the motion but nothing comes up, or what comes up isn't recognisable as fur, you're probably looking at vomiting rather than a hairball — see the vomiting guide.
A hairball obstruction is rare but serious. Signs:
- Repeated unproductive retching over more than a day.
- Refusing food for 24 hours.
- A swollen, hard abdomen.
- Constipation paired with the retching.
- Lethargy.
Any of those, call the vet. Surgery for a stuck hairball is straightforward but the cat needs to get in quickly.
When the cause is over-grooming
A cat that's suddenly producing a lot of hairballs may be grooming more than usual. Common reasons:
- Fleas or skin itch. Check the base of the tail and the belly for flea dirt; treat with a monthly preventative.
- Stress. A new pet, a move, a renovation. Cats over-groom under stress, sometimes to the point of bald patches.
- Pain. Cats lick at sore joints or a sore belly.
If the brushing and diet changes don't reduce the frequency within a few weeks, book a vet visit. Hairballs are easy to dismiss but they can be the first thing you notice when something else is going on.