why does my cat eat grass

Your cat, a creature designed from the whiskers down to eat meat, is out on the lawn chewing grass like a small confused cow. It is one of the odder things cats do, and it worries people more than it should. For most cats, most of the time, eating grass is perfectly normal. Here is what is going on, and the handful of times it is worth a second look.

nobody is completely sure, and that is the honest answer

Cats have been eating grass for as long as anyone has watched them, and the truth is science has not fully settled why. There are good theories, and probably several are true at once. It may aid digestion or help move things through the gut. It may provide trace nutrients or fibre a pure-meat diet is thin on. It may simply be an instinct inherited from wild ancestors, in whom grass helped purge parasites. What we can say with confidence is that it is a widespread, ordinary behaviour seen in perfectly healthy cats, not a sign that something has gone wrong.

yes, it often comes straight back up

You have probably noticed that grass frequently reappears not long after it went down, usually on a carpet, usually on your way out. Cats cannot digest grass well, so bringing it up is common and, on its own, nothing to panic about. It may help them clear hairballs or something that is not sitting right. That said, if the vomiting becomes frequent rather than occasional, grass is no longer the whole story, and I have set out when to worry in why is my cat throwing up.

when to actually mind it

Two things are worth your attention. First, what the cat is chewing. Grass itself is fine, but plenty of houseplants and garden plants are toxic to cats, lilies most dangerously of all, so a cat that grazes indoors needs its greenery vetted, which I cover in what foods are toxic to cats. Second, a sudden surge in grass-eating, or grass-eating alongside genuine signs of an upset cat, off its food, low, vomiting repeatedly, is worth mentioning to your vet, since obsessive grazing can occasionally flag nausea. Otherwise, the kind fix is to give an indoor cat its own pot of cat grass, grown for the purpose and safe to chew, so it can indulge the instinct without redecorating your ferns. A cat eating grass is usually just a cat being a cat. Let it have its salad.

Related reading from my desk: why is my cat throwing up, since the grass so often returns, and what foods are toxic to cats, so the indoor greenery is safe to nibble.

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