Vegetable
Can cats eat onions?
Cats are even more sensitive to onion than dogs; a small amount of onion powder in baby food or soup has caused anaemia.
Why N-propyl disulphide and related sulphur compounds
If your cat ate some
- Call your vet or a pet poison helpline straight away, even if your pet seems fine.
- Tell them what was eaten, roughly how much, when, and your pet’s weight.
- Do not try to make your pet sick unless a vet tells you to.
- Signs of anaemia can take several days to appear, so keep watching after a vet visit.
Signs to watch for
- Weakness and tiredness
- Pale or yellowish gums
- Fast breathing and heart rate
- Red or brown urine
- Vomiting and diarrhoea
Dogs and cats, side by side
Dogs Toxic
No. Onions in any form — raw, cooked, powdered or in gravy — damage red blood cells and can cause anaemia. Effects build up if small amounts are eaten often.
Can dogs eat onions?Cats Toxic
No. Cats are even more sensitive to onion than dogs; a small amount of onion powder in baby food or soup has caused anaemia.
The details
All members of the allium family — onions, garlic, leeks, shallots and chives — contain compounds that damage the red blood cells of dogs and cats. The cells burst, leaving the body short of oxygen-carrying capacity. Around 5 grams of onion per kilogram of body weight can cause changes in cats, and 15–30 g/kg in dogs.
Cooking does not make onion safe. Check labels on stock, soup, gravy, baby food and ready meals before sharing leftovers.
Safer treats your cat can have instead
Questions owners ask
Can cats eat onions?
No. Cats are even more sensitive to onion than dogs; a small amount of onion powder in baby food or soup has caused anaemia.
What makes onions risky for cats?
N-propyl disulphide and related sulphur compounds.
What are the signs to watch for in cats?
weakness and tiredness, pale or yellowish gums, fast breathing and heart rate, red or brown urine, vomiting and diarrhoea.
What should I do if my cat ate onions?
Call your vet or a pet poison helpline straight away, even if your pet seems fine. Tell them what was eaten, roughly how much, when, and your pet’s weight. Do not try to make your pet sick unless a vet tells you to. Signs of anaemia can take several days to appear, so keep watching after a vet visit.
Is onions safe for dogs too?
No. Onions in any form — raw, cooked, powdered or in gravy — damage red blood cells and can cause anaemia. Effects build up if small amounts are eaten often.
Sources
Tailwise is for general information and is reviewed by veterinary professionals, but it is not a substitute for advice from your own vet, who knows your pet. How we check facts


