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Can Dogs Eat Onions?

Raw, caramelized, or roasted onions are a staple of many dishes and are often used to add flavor to our favorite meals. If you use onions in your cooking you are probably wondering what would happen if your dog ingested onions.

So, can dogs eat onions? No, dogs can’t eat onions. Onions contain a toxic compound and even a small amount of onions can cause complications in dogs. Also, all members of the allium family, including onions, garlic, chives, scallions, leeks, and shallots are toxic to dogs. If your dog eats onions, take them to the vet asap!

In this article, we’ll tell you everything you need to know about onion toxicity in dogs, including the symptoms and treatment options. Keep on reading to learn what to do if your dog eats onions by accident. 

Are Onions Good for Dogs?

Raw, roasted, caramelized, or cooked onions aren’t safe for dogs to eat and can cause serious complications even when ingested in small amounts. Furthermore, onion powder and onion rings are no less problematic and can also cause onion poisoning in dogs. 

Unlike many other fruits and vegetables that can be beneficial for your dog’s health, eating onions can cause more harm than good to your canine sidekick.

Since they are toxic to dogs, you shouldn’t feed raw or cooked onions to your dog. Also, keep your pooch away from any type of human food that contains onions.

If by any chance your dog manages to ingest raw or cooked onion, call your vet right away or take your pup to an emergency veterinary clinic.

What Parts of Onions Are Toxic to Dogs?

What Parts of Onions Are Toxic to Dogs

All parts of onion, including flesh, leaves, skin, and even juice are toxic to dogs. As mentioned above, it doesn’t really matter if the onion is cooked, raw, or in powdered form – all of them are equally toxic. 

All types of onions, including yellow, red, and green onions contain a toxic compound known as N-propyl disulfide. Processing an onion in any way, won’t diminish its toxicity levels or make it any safer for your pooch to eat.

The toxin found in both onions and garlic has an adverse effect on your dog’s blood cells. N-propyl disulfide causes damage to your dog’s red blood cells by attaching to the oxygen molecules in your dog’s circulatory system. 

This, in turn, affects red blood cells’ ability to carry oxygen. This toxin also tricks your dog’s immune system into thinking that their own red blood cells are invaders. 

In order to defend itself from this “attack”, your dog’s body starts to destroy red blood cells using a process that is called hemolysis. This in turn causes your dog to develop a type of anemia, known as hemolytic anemia (source). 

Symptoms of Onion Toxicity in Dogs

If by any chance your dog manages to gobble large amounts of onions, you should be on the lookout for the symptoms of hemolytic anemia (source). Onion toxicity sets in pretty quickly if your dog eats a large amount of garlic or any other member of the allium family in a short time.

However, in most cases, the symptoms of onion toxicity in dogs appear a few days later. It’s also possible for N-propyl disulfide to build slowly over time especially if your dog is eating a small amount of onion or garlic over some time. 

If your dog eats onions be on the lookout for the following symptoms of anemia and toxicity:

  • Decreased appetite
  • Lethargy
  • Weakness
  • Pale gums
  • Reddish urine 
  • Fainting
  • Vomiting
  • Elevated heart rate
  • Panting

If your dog exhibits any of these symptoms, take them to the vet as soon as possible. Your veterinarian will do complete blood work and look for Heinz bodies on a blood smear to diagnose your dog’s condition properly. 

How to Treat Onion Toxicity in Dogs?

How to Treat Onion Toxicity in Dogs

The best thing you can do if you suspect that your dog is suffering from onion toxicity is to take them to the vet.

Depending on how recently your pooch ingested onions your vet may induce vomiting or flush your dog’s stomach to remove the toxin. Your vet may also decide to administer activated charcoal that will absorb the toxin from your dog’s stomach.

In some cases, intravenous fluids may be given to keep a dog hydrated and clean their bloodstream. In severe cases when a dog is very sick, the vet may administer oxygen and blood transfusion. 

The anemia caused by onion toxicity can be fatal for dogs if not treated quickly. Therefore, don’t wait around thinking that your dog will get better on its own, instead take them to the vet right away! 

How Much Onion Does It Take to Poison a Dog?

The biggest reason why onions and other members of the allium family are so dangerous is that even a small amount can cause serious problems in dogs. Toxicity occurs when a dog eats more than 0.5% of its weight in onions in a short amount of time. 

For large and giant breeds this might seem like a lot of onions, but for a tiny breed like a Chihuahua, 1 ½ tablespoon of onions may be enough to cause serious damage. 

How Much Onion Can Kill a Dog?

Your dog doesn’t have to eat a ton of onion in a single sitting to become seriously ill since N-propyl disulfide can build up in your dog’s system over time. 

Generally speaking, a 25-pound dog can develop onion toxicity after eating ¼ of a cup of onions. A 75-pound dog can reach toxic levels after eating ¾ of a cup of onions, and a 10-pound dog can become seriously ill after ingesting only a 1 ½ tablespoon of onion.  

The toxic effects of onions lead to hemolytic anemia which is a life-threatening condition when left untreated. 


While onions are a staple ingredient in many dishes and recipes they are one of the most dangerous human foods for dogs. Eating even a small amount of onions can lead to toxicity and hemolytic anemia which is a potentially fatal condition. 

Keep in mind, all members of the allium family including onions, garlic, scallions, chives, and leeks are toxic to dogs and you should keep them out of your dog’s reach. It’s worth noting that certain types of baby food and even wet dog food contain onions, so read the labels carefully to avoid poisoning your dog.

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