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Can Dogs Eat Onions? Are Onions Safe for Dogs?

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By Nicole Cosgrove

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Onions are pervasive in human diets and can be found in all kinds of foods, so many people wonder if they’re safe for dogs. Although most vegetables are okay to give your pup, onions in any form are toxic to dogs and should be very strictly avoided for canine consumption.Divider 8

Why Are Onions Toxic to Dogs?

Onions and other foods in the allium family — shallots, leeks, scallions, garlic, and chives — contain two different toxins referred to as n-propyl disulfide and n-propyl thiosulfate. According to the Journal of Venomous Animals and Toxins, these compounds are highly toxic to dogs and can cause major health issues. They note that these toxins can even be fatal in large quantities.

Experts at Wild Earth explain that these toxins affect your dog’s red blood cells and can lead to major issues like anemia and hemolysis, both of which can prevent oxygen from being transported effectively to your dog’s muscles, heart, and brain.

Can Dogs Eat Onions
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Is Cooked Onion Okay?

None of the toxins in onions are rid of or denatured through the cooking process, so cooked onions are just as dangerous as raw onions.

This means that any meal that is cooked with onion is unsuitable for your dog and could lead to poisoning. Never offer your pooch your food if you cooked with onions, and always check pre-made foods for onions or similar ingredients so you can avoid giving onion to your dog in any capacity.

What About Food Made with Onion Powder?

Just like with cooking, the process of drying onion into onion powder doesn’t get rid of the compounds that are toxic to dogs. According to the American Kennel Club, food made with onion powder is just as dangerous for your dog as eating raw or cooked onions. In fact, onion powder should be considered even more dangerous, because it is really just highly concentrated onion.

Since onions and onion powder are so prevalent in the foods we eat, you need to be very careful not to give your pup onion accidentally.

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How Much Onion Can Be Fatal for My Dog?

The answer to this question isn’t the same for every dog, and the exact amount will depend on a few factors, the largest of which is your dog’s weight.

The American Kennel Club suggests that the fatal amount of onion is about 100 grams for every 45 pounds of your dog’s body weight. For context, a large onion weighs in excess of 250 grams, so less than half of a large onion could be deadly for your dog.

Onion powder is fatal in even smaller quantities because it’s a concentrated form of onion. One tablespoon of onion powder often contains the equivalent of a medium onion, and this small amount can be fatal if consumed by your pup.

How Do I Know If My Dog Ate Too Much Onion?

If you’re not sure if your dog ate something that contained onion, you’ll need to monitor them carefully and check often for the symptoms of onion consumption.

The ASPCA notes that symptoms in your dog can include vomiting, hematuria (blood in urine), unusual fatigue, excessive panting, and an elevated heart rate. These symptoms can take some time to present themselves, so you’ll want to keep a close eye on your dog for several hours if you think they may have eaten a small amount of onion.

sick dog laying in bed
Image Credit: Lindsay Helms, Shutterstock

What Do I Do if My Dog Eats Onion?

The best practice following onion consumption by your dog depends on how much onion they’ve had. If you can be certain that they ate a very small amount of onion or a food made with onion, you can carefully watch for symptoms before taking further action. While no amount of onion is okay for dogs, a very small quantity likely won’t be fatal, especially if you have a medium or large dog.

If you find your dog munching on your onion rings or a large amount of some other food made with onion or onion powder, you should take them immediately to the vet. Take note of how much onion your dog may have eaten, and relay that to your veterinarian.

Your pup’s doctor may pump their stomach, induce vomiting, or take other measures to purge the onion and the toxins from your dog’s system before it causes major health complications.Divider 7


Onions and other foods belonging to the allium family are highly toxic to dogs and should be avoided in their diet at all costs. Even small amounts can be dangerous, and cooked onion and onion powder can be just as dangerous or more dangerous than raw onion. If your dog does get into a food that was cooked with onion, take them quickly to the vet to help limit the toxic effects this food can have on your pooch.

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