Can cats eat onions?
Onions (Allium) damage red blood cells. Cats are the most susceptible species; poisoning has been reported after less than a teaspoon of cooked onion (Merck).
Good to know: Also in baby food and gravies – don't offer these (iCatCare).
Did your cat eat some?
Call your vet or an emergency vet clinic right away, even if your cat seems fine. Tell them what your cat ate, how much and when.
- ASPCA Animal Poison Control: (888) 426-4435 (a fee may apply)
- Pet Poison Helpline: (855) 764-7661 (a fee may apply)
- Don’t make your pet vomit unless a vet tells you to.
Better choices, for example
Questions
My cat ate onions. What should I do?
Call your vet or an emergency vet clinic right away, even if your cat seems fine. You can also call ASPCA Animal Poison Control at (888) 426-4435 or the Pet Poison Helpline at (855) 764-7661 (a fee may apply). Don’t make your cat vomit unless a vet tells you to.
Can dogs eat onions?
No – toxic. Onions belong to the Allium genus and damage red blood cells, which can lead to anemia. Raw, cooked, dried and powdered forms are all dangerous, and signs often appear only days later.
Sources
- Merck Veterinary Manual – Garlic and Onion (Allium spp) Toxicosis in Animals
- ASPCA Animal Poison Control – People Foods to Avoid Feeding Your Pets
- Cornell Feline Health Center – Common Cat Hazards
- International Cat Care – How to encourage your cat to eat
- Pet Poison Helpline – Onion
Last checked: October 2026