A dog with a concerned expression looking at onions, indicating it's toxic for dogs.

Can Dogs Eat Onions?

No, dogs should not eat onions. Onions are highly toxic to dogs, regardless of whether they are raw, cooked, or in powdered form. Eating onions can cause serious health issues, as they contain compounds that damage red blood cells, potentially leading to a dangerous condition called hemolytic anemia.

A photo of Stefan Stumpfl, the co-author of this article.

By Stefan Stumpfl, in collaboration with Dr. Ali Raza.

Updated on Jun 19, 2024

Did You Know?

Onions contain compounds that can break down a dog’s red blood cells, leading to anemia.




Rating: 1 out of 5 stars🍏


Rating: 1 out of 5 stars🍪


Rating: 1 out of 5 stars👍

Feeding Frequency


Allergic Risk


Why are Onions Bad for Dogs?

Onions contain thiosulfate, which dogs cannot digest properly. This substance can destroy red blood cells, leading to anemia. Even small amounts can be harmful, causing symptoms like lethargy, pale gums, and weakness. Severe cases may require blood transfusions and other intensive treatments.

How Much Onion Can Dogs Eat?

Ideally, dogs should eat no onions at all. Even a small quantity can be risky, particularly for smaller breeds. If your dog accidentally consumes a tiny piece, they might be fine, but it’s best to err on the side of caution and keep onions completely out of their diet.

Similar Toxic Products

Onions aren't the only kitchen culprit. Be cautious with:

  • Garlic: Similar to onions, garlic is even more concentrated and can be more toxic.
  • Chives: Another member of the Allium family, these too can cause similar symptoms of toxicity.
  • Onion Powder: Often found in soups, stews, and spice mixes, it can be particularly risky since it's easy to overlook.

What to Do If Your Dog Eats Onions?

If your dog eats onions, call your vet immediately. Do not attempt to induce vomiting unless advised by a professional, as this can sometimes cause more harm than good. Your vet will guide you through any emergency actions and may ask you to monitor your dog for symptoms.

Signs and Symptoms of Onion Poisoning in Dogs

Look out for these symptoms if you suspect your dog has eaten onions:

  • Vomiting
  • Diarrhea
  • Lethargy
  • Weakness
  • Pale gums
  • Rapid breathing

How Long After Eating Onion Will a Dog Get Sick?

Symptoms can appear within a few hours but might take days to become fully visible. Quick intervention is crucial.

When to Contact Your Vet for Advice?

Contact your vet immediately if you notice any symptoms or if you know your dog has ingested onions.

How to Treat Onion Poisoning in Dogs?

Treatment for onion poisoning usually involves supportive care such as intravenous fluids, oxygen therapy, and in severe cases, blood transfusions. The duration of treatment can vary based on the severity of the poisoning. Post-treatment, your dog might need a follow-up to ensure they’re recovering properly.

And now, the not-so-fun part: costs. Treatment could run anywhere from a few hundred to several thousand dollars, depending on the severity and required procedures. Having pet insurance can significantly ease the financial burden, making it a smart move for any dog parent.

What are Healthy Alternatives?

Fortunately, there are plenty of other delicious and safe treats for your pup. Consider:

  • Carrots: Crunchy and full of vitamins.
  • Apples: Just remove the seeds and core.
  • Green beans: Low in calories and dogs love the crunch.


In summary, onions are a definite no-no for dogs. They pose serious health risks and are best kept out of your pet’s reach. Always consult with your vet for advice if you're ever in doubt or if any symptoms arise. Keep your furry friend safe and happy with healthier treats, and always double-check any new food you plan to introduce into their diet.