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Can Dogs Eat Onions? If Your Dog Ate Onions, What Do You Do?

Can dogs eat onions? And what are your next steps if your dog ate onions? The facts about onions and dogs are a little complicated — let’s find out more.

Sassafras Lowrey  |  May 4th 2018


Onions are unique members of the root vegetable family because they (like garlic) are bulbs and do not grow as deeply as other root vegetables. Onions come in white, yellow and red bulbs, as well as chives and leeks, and are a common flavorful addition to meals and side dishes, served both cooked and raw. They help bring flavor to many of our favorite dishes, but can dogs eat onions? If your dog ate onions, what do you do?

First, what to know about dogs and onions

Dogs with grapes, chocolates, onions and other toxic foods.

Grapes, chocolates, onions and other some other humans foods are toxic to dogs. Photography ©humonia | iStock / Getty Images Plus.

Most lists of human foods toxic to dogs include onions. We spoke with Emmy-award winning veterinarian Dr. Jeff Werber to learn more about how dangerous onions are for our dogs. Dr. Jeff explains that while onions aren’t great for dogs, they might not be quite as bad for them as most of us thought. “Traditionally, we have always recommended avoiding raw onions and raw garlic because of a type of toxin that can have a negative effect on red blood cells,” Dr. Werber confirms.

So, can dogs eat onions?

Well, you shouldn’t give your dog a bowl of onions to snack on. Onions aren’t healthy for dogs, but unlike grapes, where even a small amount can be toxic, onion toxicity depends on how much of an onion a dog consumes. “We have found that a dog would have to ingest a very large amount for it to become a problem,” Dr. Werber advises.

However, one of the dangers of onions and dogs is that the toxins can build up in their system, meaning that they could slowly be reaching a point where an onion exposure could get them sick, or that there might be what Dr. Werber calls a cumulative effect. “To be safe, avoid onions and garlic,” Dr. Werber suggests. Consuming onions can lead to dogs developing a condition called hemolytic anemia. This condition impacts/destroys a dog’s red blood cells, leaving dogs without enough of them for healthy functioning. Severe onion poisoning in dogs can be fatal.

What should you do if your dog ate onions?

To be safe, keep all onions and all products containing onions away from your dogs. But, what happens if you’re cooking and you drop a slice of onion on the floor or a friend shares a bite of their lunch with your dog and it includes onion? While we don’t want our dogs eating onions, having a bite of something with onion isn’t likely to make your dog sick. “Your dog probably would not eat enough to cause a real problem because dogs typically don’t like the taste,” Dr. Werber says.

If you think your dog ate onions in large quantities, or if your dog seems like he isn’t feeling well, Dr. Werber suggests seeking immediate veterinary care. Your veterinarian will be able to evaluate your dog and determine if any treatment is necessary.

Thumbnail: Photography © vvuls | iStock / Getty Images Plus. 

Sassafras Lowrey is an award-winning author. Her novels have been honored by organizations ranging from the Lambda Literary Foundation to the American Library Association. Sassafras is a Certified Trick Dog Instructor, and assists with dog agility classes. Sassafras lives and writes in Brooklyn with her partner, a senior Chihuahua mix, a rescued Shepherd mix and a Newfoundland puppy, along with two bossy cats and a semi-feral kitten. Learn more at sassafraslowrey.com.

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Read more about what human foods dogs can and can’t eat on Dogster.com: