Can Dogs Eat Onions? Everything You Need to Know

No, dogs cannot eat onions. Onions are popular flavor enhancers commonly found in foods. However, they are pretty poisonous in all forms and unsuitable for your dog’s consumption. Furthermore, when consumed in significant quantities, they damage the dog’s red blood cells leading to serious health consequences like hemolytic anemia.

What are Onions?

Onions are vegetables belonging to the species of the genus Allium. It is consumed either raw or used as a flavor enhancer with a pungent smell. Onions are cultivated worldwide, and their origins can be traced back to the Bronze age where traces of onions were recovered. In addition, they were also found in Egyptian burials and Pompeii, the earliest known Roman settlements. 

Types of onions

  • White Onions
  • Red Onions or Purple Onions
  • Yellow or brown Onions

Nutritional Information

Although onions are toxic to dogs, they are quite nutritious and contain the following nutrients:

One cup of chopped onions
Carbohydrates14.9 g
Fats0.16 g
Sugar6.78 g
Fiber2.72 g

Are Onions Safe for Dogs?

No, onions are toxic to dogs. Whether raw, cooked, or processed, all parts of onions are unsafe for a dog’s consumption. Onions contain a substance called thiosulfate that cannot be digested by dogs.

Why Are Onions Bad for Dogs?

All parts of the onion plant, like its flesh, leaves, juice, and processed powders, are toxic. In addition, even in cooked, fried, or powdered form, they pose the same risk. This is because onions contain a poisonous compound called N-propyl disulfide that attaches to your dog’s red blood cells through its oxygen molecules. This attachment hampers your dog’s ability to carry oxygen. As a result, your dog’s immune system assumes these cells to be invader cells and destroys the red blood cells by a process known as hemolysis. When left unchecked, it leads to hemolytic anemia or symptoms of onion toxicity in dogs. Further consumption of onions can lead to liver damage, asthmatic attacks, allergic reaction, weakness, diarrhea, discolored urine, vomiting and dermatitis.

How Much of Onions to Feed Your Dog?

Onion toxicity occurs if a dog consumes onions by more than 0.5% of its body weight at a single serving. This means that even smaller consumption of onions as low as 100g of onion can easily poison per 20 Kg of a dog’s body weight. This is another reason dogs shouldn’t be fed onions even in smaller quantities, especially for smaller dog breeds. Hence, onions should never be fed to dogs. 

What If My Dog Ate Onions? 

If your pet accidentally consumed a sliver of onion on the floor or someone shares a bite of their lunch with your dog, your canine mate may not show any ill effects. However, suppose he ate it in significant quantities at a single serving. In that case, the impact of toxicity can quickly establish or, in some cases, may appear after a few days after ingestion. This is because N-propyl disulfide may build up slowly in his blood due to the consumption of smaller quantities of onions over a period of time. In this case, you need to know the symptoms of onion toxicity to act timely: 

Symptoms of onion poison in dogs

If you feel your dog may have eaten onions, look out for symptoms of anemia:

  • Lethargy
  • Weakness
  • Decreased appetite
  • Pale gums
  • Fainting
  • Reddish urine
  • Vomiting
  • Elevated Heart Rate
  • Panting
  • Ataxia

If you see any of the symptoms mentioned above in your dog, reach out to your vet immediately to help him, as onion toxicity can be fatal to dogs. Once there, your vet will diagnose his condition depending on his symptoms and blood samples. He may isolate the blood sample and detect the formation of Heinz bodies. When this discovery is combined with the recent onion exposure, your canine mate may be diagnosed with onion toxicity. However, other conditions may also cause hemolytic anemia in dogs. 

Treatment Options for Onion toxicity in dogs

Your vet may suggest the following treatment options for ensuring normalcy for your dog, they include: 

  • Vomiting may be induced to flush his stomach with toxins.
  • Activated charcoal may be introduced to absorb the toxicities from the gut.
  • Intravenous fluids may be administered to flush your dog’s bloodstream and maintain hydration. 
  • In severe cases of toxicity, your vet may order a blood transfusion. 

Preventing dogs from eating onions

The best way to keep your dogs away from onions is:

  • Keep unsafe ingredients away from your dogs to prevent them from eating them.
  • The garden fence contains herbal plants that are quite toxic to dogs.
  • Please dispose of the waste so your dogs can’t access it later. 

Alternatives to Onions

Some dog-safe foods like some vegetables, fruits, or meat contain the same nutritional components like

  • Bananas
  • Bok-choy
  • Blueberries
  • Salmon
  • Butternut Squash
  • Crabmeat
  • Cilantro
  • Jicama
  • carrots
  • cucumbers
  • green beans

Frequently Asked Questions

Can Dogs Eat Scallions?

No, scallions should not be fed to dogs. They are young onions, and they are toxic as well.

Can Dogs Eat Garlic?

No, dogs should not be given garlic, as when dogs chew them, the garlic releases organosulfur compounds that are harmful to dogs.

Can Dogs Eat Chives, Leeks, or Shallots?

No, dogs cannot be fed with these vegetables since they also belong to the allium family and are equally harmful as onions.

Can Dogs Eat Broth Cooked With Onions?

No, any recipe that contains onions should not be fed to dogs as they may have the essence.


As dogs are our best friends, we need to care for them. Although they might entice us with their naughtiness, we must prioritize their safety and health over their fondness for food. This makes your pet healthy and makes you a happy pet parent.

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