Onions contain compounds that damage red blood cells, which then break down faster than the body can replace them (haemolytic anaemia). Toxicity can build up from one large meal or from small amounts eaten repeatedly. Concentrated forms such as onion powder are especially risky. The AKC notes Japanese breeds such as Akitas and Shiba Inus are more susceptible. Leeks, shallots, spring onions and chives belong to the same family and are toxic too.
No: toxic
No. Onions in any form (raw, cooked, fried, dried or powdered) damage dogs' red blood cells and can cause anaemia. Signs can be delayed by several days. Watch for onion in gravy, stock, baby food, takeaways and seasoning mixes.
This guide is general information, not a diagnosis. If your pet seems unwell, or you're worried, call your vet.
Why onions are dangerous for dogs
If your dog ate some
- Call your vet, an emergency clinic or a pet poison line straight away, even if your pet seems fine. Many poisonings are easier to treat before signs appear.
- In the US: ASPCA Animal Poison Control (888) 426-4435 or Pet Poison Helpline (855) 764-7661. Both may charge a consultation fee.
- Note what was eaten, roughly how much and when, and keep the packaging.
- Don't make your pet vomit unless a vet tells you to; it isn't always safe.
- Use our onion and garlic calculator to estimate the risk, and call your vet.
- Your vet may make your dog vomit if it was recent, and check blood counts over the following days.
Signs to watch for
- Vomiting, diarrhoea or drooling (early)
- Pale gums
- Weakness, tiring easily or collapse
- Fast breathing or a fast heart rate
- Red or brown urine
- Signs may appear 1 to 5 days after eating
Collapse, seizures, difficulty breathing or pale gums are emergencies: go to the nearest vet straight away.
Other foods for dogs
Also no: toxic
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We check guides against veterinary sources and update them when guidance changes. How we write and review.
Questions.
Can dogs eat food cooked with onion?
It's best not to. Small traces are unlikely to cause problems in a large dog, but gravies, sauces and stocks can contain a lot of onion, and repeated small amounts add up.
Are spring onions and leeks toxic to dogs?
Yes. All members of the onion family (Allium), including leeks, shallots, spring onions and chives, are toxic.
