My 6 kg senior cat ate two cooked Brussels sprouts that were left out overnight and look a bit

Short answer

The mould is the problem, not the sprouts themselves. Mould can contain toxins that cause vomiting, diarrhoea, or even neurological signs like tremors in cats. Watch for any gastrointestinal upset in the next 6 to 12 hours. Offer plenty of fresh water to help flush her system. If she acts lethargic, refuses food, or starts vomiting, call your vet. For future safety, store cooked vegetables in the fridge and discard anything that's been out more than two hours. Plain, fresh Brussels sprouts are safe in tiny amounts, but always serve them fresh.

Brussels sprouts — Food safety facts

Safe to share · Cats · full breakdown on the linked food page

Safe cooked and plain, but they cause gas in larger amounts.

Dogs and cats carry the same rating (Safe to share), so the notes below hold for either pet.

Brussels sprouts is not toxic to cats. The real limit is calories, fat and salt, so treat it as a small extra alongside the normal ration rather than a meal in itself.

There is no poisoning risk here, and the usual problem is simply eating too much at once: a heavy fat or salt load can bring on loose stools or a single vomit. Offer water, keep an eye on the pet for 24 hours, and do not induce vomiting.

Brussels sprouts can stay on the rotation, but only as an extra mouthful: keep the rest of the day's food unchanged and watch the litter box and how quickly they finish the next meal.

The full verdict, portion guidance and serving notes are collected on the Brussels sprouts food facts page.

Open the full food page: Brussels sprouts food facts →

My 6 kg senior cat ate two cooked Brussels sprouts that were left out overnight and look a bit mouldy. What should I do?

Brussels sprouts — Food safety facts

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