Hairballs in cats: when they are normal and when they are not
Hairballs have become so normalised that many owners assume a cat brings up hair every week. That is not the case. The odd hairball is within what you would expect; lots of them are not, and sometimes what looks like a hairball is something else.
Where they come from
A cat's tongue is covered in small hook-shaped papillae that work like a comb. When grooming, which can take up a good part of the day, the cat pulls out dead hair and swallows it. Normally almost all that hair moves through the gut and comes out in the faeces without you noticing. When too much builds up in the stomach, it compacts with juices and mucus into an elongated cylinder (a trichobezoar) that the cat brings up by vomiting. That is why hairballs are shaped more like a sausage than a ball: they take the shape of the oesophagus on the way out.
How many is too many
There is no official figure, but feline vets agree that a healthy shorthaired cat should bring up hairballs only rarely, and that more than one or two a month warrants a visit. In longhaired cats (Persian, Maine Coon, Norwegian Forest Cat, Ragdoll) and during moulting it is more common, but it still should not be weekly. Frequent hairballs usually point to one of two things: the cat is swallowing far more hair than normal because they overgroom, or their gut is not moving its contents along properly. Both have a cause, and that cause is what you need to find.
When they groom too much
A cat that overgrooms swallows more hair. Behind it there may be itching from fleas, food or environmental allergy, mites, ringworm, or pain in a specific area, for example the belly with cystitis or a joint with arthritis. Stress too: changes at home, a new cat, a house move. Look for areas where the fur is shorter or thinner, especially on the belly, the inner thighs or the flanks, and watch whether they lick insistently. If the hairs in those areas are broken rather than shed, the cat is pulling them out.
When the problem is the gut
In adult and older cats, frequent hairballs are often a clue to an underlying digestive problem that makes the stomach and intestine empty more slowly: chronic enteropathy (what used to be called inflammatory bowel disease, IBD), low-grade intestinal lymphoma, which is common in older cats, or motility problems. If they also vomit food or liquid, have diarrhoea or soft stools, lose weight or eat less, it is no longer about hair: they need a check-up with blood tests and probably an abdominal ultrasound. Treating a cat with a gut problem with malt paste only delays the diagnosis.
Watch out: an asthma cough looks like a hairball
It is one of the most common mix-ups in feline practice. A cat with asthma or bronchitis coughs crouched low to the ground with the neck stretched forward, making a dry, repeated noise, as if trying to bring something up. Many owners describe it as "trying to bring up a hairball but nothing comes out". If that episode keeps happening and the hairball hardly ever appears, film it and show it to your vet. Feline asthma is common and treats well, and if it is mistaken for hair for months the airways get damaged. And if during any episode they breathe with the mouth open or struggle to breathe, it is an emergency.
When a hairball is an emergency
Rarely, a hairball that is too large will not come up or go down and blocks the stomach or intestine. The signs are repeated retching without bringing anything up, vomiting everything they eat, loss of appetite, lethargy, constipation or no faeces, and a belly that hurts when touched. A cat with those symptoms needs to see the vet the same day, not least because a cat that stops eating for more than a day or two is at risk of developing hepatic lipidosis (fatty liver). The vet will confirm the blockage with X-rays or ultrasound; some are resolved with medical treatment and others need surgery.
Prevention: brushing works best
Every hair you remove with the brush is a hair that does not get swallowed. In shorthaired cats one or two sessions a week are enough, stepped up during the spring and autumn moults. In longhaired cats, ideally a little every day, because you also prevent the mats that end in a shave-down. Use a fine-toothed slicker or a rubber grooming mitt on short coats, and a metal-toothed comb combined with a brush on long coats. Keep it short and pleasant, with treats, and stop before the cat gets bored. A cat used to the brush from kittenhood experiences it as stroking; one who discovers it as an adult needs more patience.
Malt, fibre and special diets
Malt pastes and lubricant laxatives for cats help hair move through the gut and can be useful during moulting periods or in longhaired cats, always following the pack instructions or your vet's advice and without making them a daily, indefinite thing. "Hairball control" dry foods contain more fibre, which helps transit; some cats do well on them. Offering cat grass now and then for them to nibble is optional. What you should not do is give cooking oils, petroleum jelly or other home remedies by the spoonful: besides the unnecessary fat, a cat that inhales an oil can develop pneumonia.
Water and activity matter too
A well-hydrated, active gut moves hair along better. A cat that eats only dry food and drinks little has drier faeces and slower transit. Including wet food in the diet, offering water in several places around the home, away from food and the litter tray, or trying a water fountain, all help. Daily play, besides keeping them fit, reduces boredom grooming. In overweight cats, losing weight helps too: an obese cat cannot reach certain areas to groom, mats form and dead hair builds up.
What to tell your vet
If hairballs are frequent, note how often the cat vomits, whether what comes up is just hair or also food or liquid, whether they eat and drink as usual, what their faeces are like, whether their weight has changed and whether you see them licking more. A photo of the vomit and a video of the episodes are very useful, especially to tell vomiting from coughing. In Spain a consultation usually costs 40 to 60 €; if blood tests and an abdominal ultrasound are needed, expect around 150 to 300 € in total. It is money well spent if it saves months of hairballs that were really asthma or a gut problem.
The odd hairball is normal; more than one or two a month is not. Brushing is the best prevention, and if hairballs are frequent, or the cat also vomits food, loses weight or "tries to bring something up" without success, it is time for a check-up: it could be a gut problem or asthma.
Educational content from Michipedia, translated from the Spanish original. It does not replace the advice of a vet or a feline behaviour specialist. Every cat is an individual.