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Can cats eat onion?

Unsafe

Quick verdict

Unsafe

Key risk

Cats are especially sensitive; even small amounts can cause anaemia.

Why

Onion is highly toxic to cats and must be avoided.

Can cats eat onion, and why?

Onion is highly toxic to cats and must be avoided. Cats are especially sensitive; even small amounts can cause anaemia.

Cats are obligate carnivores: they must get most of their nutrition from meat and need nutrients such as taurine that only animal products provide. They lack some enzymes for processing plants and carbohydrates, so fruit and veg offer little benefit and can upset their stomach; many cats are also lactose intolerant.

Warning — what to watch for

Cats are especially sensitive; even small amounts can cause anaemia.

If your cat has eaten onion, don’t wait for symptoms — contact your vet immediately, or call the Animal PoisonLine on 01202 509000 (24/7, UK). Signs of a problem can include vomiting, diarrhoea, drooling, lethargy, tremors or loss of appetite.

More foods cats might eat

Make treat time better

Handy kit for feeding cats well:

Frequently asked questions

Can cats eat onion?

Unsafe. Onion is highly toxic to cats and must be avoided.

What happens if my cat eats onion?

Cats are especially sensitive; even small amounts can cause anaemia. If your cat has eaten onion, contact your vet or the Animal PoisonLine (01202 509000) straight away — don’t wait for symptoms.

Is onion poisonous to cats?

Unsafe. Onion is highly toxic to cats and must be avoided.

Check onion for another pet

General guidance based on established veterinary sources (ASPCA, PDSA, Blue Cross, RSPCA), not a substitute for advice from your vet. If you’re ever unsure, or your pet has eaten something harmful, contact your vet or the Animal PoisonLine on 01202 509000.