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Are Onions Bad For Dogs?

January 10, 2022 | 3 min read

Updated January 10, 2022

By Sarah Milton

Published: January 10, 2022
Updated: October 25, 2022

Summary: If you’re asking whether dogs can eat onions or not, in this blog we learn whether dogs can have onion and if onions are bad for dogs…    

Can Dogs Eat Onion?

Under no circumstance should a dog eat onion. Onions are one of the most toxic foods for a dog to consume. 

You should always keep onions high, contained, and hidden away from prying paws or nosey noses. 

Can Dogs Have Cooked Onion?

No. Cooked, raw and fried onions are all toxic to dogs, including onion rings.

Can Dogs Have Onion Powder?

No. All forms of onion are toxic to dogs: powdered, processed, juiced, and even onion leaves and skin. Garlic, shallots, leeks, and chives are harmful to dogs too as they’re all part of the same family (the allium family).

Onion powder appears in a lot of foods dogs could easily get their paws on like soup and baby food. And, just a small amount of onion can cause toxicity symptoms in our pups too. 100g of onion over 44lbs of a dog’s body weight can poison a dog. This means they’d only need to eat one medium to large onion to potentially be poisoned to a dangerous level.

a mixture of brown and red onions

Why Dogs Can’t Eat Onions

Onions contain a chemical called N-propyl disulfide; a sulfur compound. N-propyl disulfide attaches to the oxygen molecules present in a pup’s red blood cells which in turn prevents these molecules from taking oxygen around the body efficiently. This then tricks the body into thinking that its own red blood cells are a threat which then triggers hemolysis to take place. This is where the body attacks its own essential red blood cells. 

If hemolysis isn’t stopped, this will lead to hemolytic anemia which means the red blood cells are being destroyed faster than the body can make them. This can be fatal in dogs. 

Symptoms Of Onion Poisoning In Dogs

If you suspect your pooch has gotten hold of some onion, the symptoms of hemolytic anemia include:

  • Lethargy
  • Disinterest in food
  • Weakness
  • Reddish urine
  • Pale gums
  • Fainting or collapse
  • Weakness
  • Vomiting
  • Panting
  • Elevated heart rate

If you spot any of these signs, get your dog to a vet as soon as possible. 

My Dog Ate A Small Piece Of Onion - What Do I Do?

If you know your dog has eaten an onion, no matter how small, contact your vet. If they start displaying any of the above symptoms, get them to a vet pronto. Your vet will examine the symptoms and your pup’s blood work to determine if onion toxicity is occurring. Hemolytic anemia can be a symptom of many other conditions so a veterinarian consultation is vital. 

If onion poisoning is confirmed, your vet may attempt to induce vomiting in your pup and provide support and care to your dog until they are making enough red blood cells. If the case is really bad, a blood transfusion may need to take place.

The faster you act on your knowledge or suspicions regarding onion consumption by your dog, the better.

For your reference, here’s a list of other foods that can be incredibly toxic to dogs…

a blue and white infographic detailing which foods are toxic for dogs to consume

Why Not Try These Vegetable Alternatives?

So, as we’ve established, onions are a no-go zone for our pups. However, vegetables can play a great role in your doggy’s diet and help boost their vitamin and fiber intake! Try feeding your dog small bits of cucumber, carrots, or green beans either as treats or add them to their bowl at mealtimes.


Author Burke, Anna "Can Dogs Eat Onions?" May 11. 2017, American Kennel Club

"Can Dogs Eat Onions? Are They Bad For Dogs?" Wild Earth

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Thanks for reading


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Sarah Milton

Authored By

Sarah Milton

Comes from a family of animal lovers and got to grow up with a menagerie of pets! I believe owning a pet is a privilege and I love researching and creating informative, fun content for fellow pet owners to help their furry friends have the happiest and healthiest lives. When I’m not writing blogs, you can find me sharing a walk with my pet dachshund or at a yoga class!




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The information contained within this site is not intended as a substitute for professional medical or veterinary advice. PetLab Co. is not intended to diagnose, treat, cure or prevent any disease. If your pet has, or you suspect your pet has any medical condition, you are urged to consult your veterinarian. Medical conditions can only be diagnosed by a licensed veterinarian. These statements have not been evaluated by the Food and Drug Administration. Results May Vary. Not intended for human consumption. Please consult your veterinarian regarding any change in treatment or supplementation.
*In Amazon Pet Health Category in 2022