Can cats eat onion or garlic?

No. Onion, garlic, chives and leeks can damage a cat's red blood cells, and cats are more sensitive to them than dogs. Cooked, raw or powdered all count, and powders and seasoning mixes are especially concentrated.

That rules out most curries, gravies and leftovers. If your cat has eaten food containing onion or garlic, call your vet and tell them roughly how much.

General guidance, not a substitute for your vet. If your cat seems unwell, call them.