Why your cat keeps being sick

Cats have somehow convinced us that being sick is just something they do. Someone stands on a cold patch in the dark, a hairball turns up on the rug, and we sigh and reach for the kitchen roll. A rare sick-up genuinely is nothing to worry about. But “my cat is often sick” is a sentence I would gently push back on, because frequent vomiting is not normal, and cats are experts at looking fine while something is quietly wrong.

Before we go on, the usual honest note: I am a writer, not a vet. What follows will help you tell the routine from the concerning and know when to pick up the phone. It does not replace an actual examination, and where the signs below point to a vet, please go.

What counts as normal, and what does not

The first useful thing is to draw a line between the everyday and the not, because the two get lumped together as “sick” and treated the same.

An occasional hairball, especially in a long-haired cat, is part of normal life. The odd single vomit in a cat that is otherwise bright, eating well, and behaving normally is usually nothing. What is not normal is vomiting that happens often, several times a week or more, or that keeps going over a day, or that comes with any other sign that your cat is unwell. The frequency and the company it keeps matter far more than the single event. One sick-up from a happy cat is different from three from a cat that has also gone quiet and off its food, even though they can look similar on the floor.

So the question to ask is not just “was my cat sick” but “how often, and how is the cat in itself”.

The common, less worrying causes

Plenty of vomiting has a fairly ordinary explanation, and it is worth knowing these so you neither panic nor dismiss too quickly.

Eating too fast is a classic. A cat that gulps its food can bring it straight back up, undigested, minutes later, simply because it went down too quickly. Smaller, more frequent meals or a slow feeder often sorts this out. A sudden change of food can upset the stomach, which is why diet changes are best done gradually over a week or so. Hairballs, within reason, come with the territory of a self-grooming animal. And some cats are sick after eating something they should not have, from a bit of human food to a nibbled houseplant.

The trouble is that these ordinary causes can look identical to the start of something more serious, which is why frequency and the cat’s overall state are your guide rather than the vomit alone.

When it needs a vet

Some vomiting can be watched for a short while. Some should be seen. Contact your vet promptly if any of these apply:

The vomiting is frequent or keeps up over a day rather than being a one-off. Your cat is also lethargic, hiding, off its food, or clearly not itself. There is blood in the vomit, or it looks like coffee grounds. Your cat is losing weight, or drinking and weeing noticeably more, alongside the sickness. The cat is retching repeatedly but bringing nothing up, or its belly looks bloated or is tender. Or your cat cannot even keep water down, which leads to dehydration quickly and is more dangerous in cats than people often realise.

Behind persistent vomiting can sit a whole range of things, from a gut condition or food intolerance to kidney or thyroid problems, an obstruction from something swallowed, or others besides. You cannot tell which from home, and you are not meant to. That is the vet’s job, with the history you have gathered to point them in the right direction.

The short version is this: do not let a cat’s casual attitude to being sick convince you it is always fine. A rare hairball, no drama. Regular vomiting, or vomiting in a cat that also seems unwell or off its food, is your cat telling you something, and it is worth listening to early rather than after a week of mopping up. When in doubt, the phone call to the vet is never the wrong move.