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Can Dogs Eat Onions? Risks, Side Effects & Treatment

Onions make fantastic and delicious foods to top off our hamburgers, hotdogs and other foods. In fact, onions are one of the world’s healthiest foods, providing humans with amazing health benefits, including 27% of our recommended daily value of Biotin. But onion-loving dog owners may be asking, can dogs eat onions?

As a responsible dog owner, it’s always a good idea to question any and all human foods before feeding them to your dog. There are a lot of unsafe human foods for dogs, such as chocolate and grapes. But can dogs have onions?

No, Dogs Cannot Eat Onions.

Dogs cannot and should not eat onions without any exceptions. Whether they are cooked, raw, diced or even in powdered form, onions should be avoided by your dog. Although onions are delicious, the reality is that they can make your dog very sick.

Let’s further investigate why onions are so detrimental to your dog’s health.

Why Can’t Dogs Eat Onions?

Dogs can't eat onions because they contain Thiosulfate, which can't be digested by dogs.

Bulb onions are great for humans, but toxic to your dog. The popular vegetable contains a substance called Thiosulfate, which is harmful for dogs when ingested. Thiosulfate is okay for humans because we have the enzyme that can properly digest the substance. However, this is not the case with your canine. Without the enzyme to digest Thiosulfate, the substance can harm your dog.

In addition, onions also carry a substance called organosulfur. This compound has been known to elicit a medical condition in dogs, where the poison can easily become absorbed by the dog’s digestive system.

This is not to say that your dog is going to be in critical condition if they eat any onions at all. Accidentally eating a slice of pizza with a few pieces of onions may likely do no damage to your dog. However, when your dog ingests a lot of onions, the toxicity will really start to take a toll on them.

Side effects and potential risks will occur with dogs that consume any amount of onions. With that said, it’s in both you and your dog’s interest to leave out the onions altogether.

Risks of Dogs Eating Onions

There are tons of risks and side effects that may occur if your dog eats enough onions.

So what exactly will happen if your dog eats a significant amount of onions? If taken in a large amount, onions can pose the following risks on your dog:

  • Liver damage
  • Asthmatic Attacks
  • Severe Allergic Reactions
  • Diarrhea
  • Vomiting
  • Discolored Urine
  • Anemia
  • Fatigue
  • Dermatitis

If you see any of these symptoms in your dog shortly after consuming any quantity of onions, it’s best to pay a visit to your vet. The local veterinarian will be able to run some tests and do necessary treatments if your dog is in a critical condition from onion toxicity.

Onions and Heinz Body Anemia in Dogs

Onion toxicity in dogs can lead to serious dog health problems, such as Heinz Body Anemia in dogs. But what is this medical condition and what does it mean for your dog?

Heinz Body Anemia is one of the most common critical conditions that happen from onion toxicity in your dog. This medical condition happens when the dog’s red blood cell count significantly decreases, thus causing anemia.

Of course, the possibility of anemia will heavily depend on the amount of onion that is consumed by the dog. It’s worth noting that it’s more harmful to feed your dog one large serving of onions than small servings through an extended amount of time. This is also true regarding the development of Heinz Body Anemia in dogs.

There are common symptoms for Heinz Body Anemia. Such warning signs include brown/red colored urine, depression, pale mucous membranes of the gums and a rapid respiratory rate (fast breathing and panting). Other symptoms such as fatigue, vomiting, diarrhea and loss of appetite may also occur.

My Dog Ate Onions – What to Do?

If your dog accidentally consumes onions, don't worry. Just follow these steps and your dog will be fine.

Depending on how much onion your dog ate, there are action steps to take. If your dog only ate a few slices of onions, then there may not be any further treatment necessary. For example, if your dog ate a pizza with a few slices of onions. Or, if your dog ate a few onion pieces that accidentally dropped on the floor as your were chopping onions.

However, even with consumption of a small amount of onions, dog owners should observe their canine pets closely for any symptoms. Ingesting small quantities of onions won’t usually do much, however there can always be exceptions.

Large Quantity of Onions Consumed by Dog

In the case that your dog accidentally ate a large serving of onions, then there are steps you may want to highly consider. Also, I should note that large dogs can consume more onions  than smaller dogs before showing symptoms. Regardless, all dog breeds can be affected from onion toxicity.

1. Get the Onions Out of Dog

The best and quickest way to get onions out of your dog is to induce vomiting. This is not something any dog owner wants to do, but is necessary in some cases. The quicker you do this, the more onions (and toxins) you will be able to get out. Do this as soon as your can.

To induce vomiting in your dog, simply push the “button” on the back of their throats until they start to vomit. I must warn you this is a very unpleasant experience, but it’s better than letting them potentially suffer more later.

2. Absorb the Onion Toxin in Dog

The best way to absorb the poison in onions before your dog’s body does is by using activated charcoal. Yes, you heard right. Dogs won’t be very eager to eat activated charcoal, so try to do your best.

If you don’t have any activated charcoal lying around, there is another way. Grab some bread and put it in the toaster. Try to toast the bread until it becomes a charred dark black. The more charred, the better. Not surprisingly, dogs aren’t very eager to eat this severely toasted piece of bread.

3. Take Your Dog to the Vet

If you can quickly get to your local vet, the second step can sometimes be skipped. But whether you go through the first two steps or not, you should end up taking your dog to the veterinarian. Your veterinarian will take all the necessary steps to fully flush out the rest of the toxins in your dog’s stomach.

In extreme cases or prolonged exposure to onion toxicity, the animal hospital will have different measures of treatment for that. Most of a time for severe cases, a blood transfusion and/or therapy for liver will be required of the dog. The possibility of the development of Anemia may require constant monitoring and care.

4. Give Your Dog Some Rest

Your dog will be exhausted, especially if they had to go through the steps necessary to expunge the stomach of onion toxins. This means that it is not the greatest idea to take them out for runs and whatnot.

Make sure they stay hydrated with plenty of water in their system. It helps with their recovery from any foreign poison and toxin. Your vet should have further instructions for recovery based on your specific case. Don’t worry, your dog will be completely fine in no time!

Dogs: Alternatives to Eating Onion

Although it’s true that onions are not something dogs should eat, there are many safe vegetables your dog can eat and benefit from. Here is a list of just a few vegetables that are great for dogs to eat from time to time. Make sure to always research on whether a dog can eat a specific human food before feeding them to your dog.

Safe and Healthy Vegetables For Dogs

Cucumbers are nice, refreshing vegetables your dogs can eat on a hot sunny day. Not only are cucumbers perfect in keeping your dog hydrated, but they are packed with a ton of vitamins like Vitamin K. The K vitamin is responsible for keeping your dog’s bone density strong and healthy. The most important part is that they aren’t toxic to dogs, like with onions.

Another healthy vegetable for dog with even more Vitamin K is celery. Although celery are safe for dogs to eat, there specific preparations necessary before feeding them to dogs. Pro-tip: celery can be used as a natural floss to help clean the junk stuck in your dog’s teeth.

Broccoli is one of the healthiest vegetables. There is no exception for your dog. Broccoli is loaded with all types of vitamins and minerals that your dog can certainly benefit from. They can help your dog with bone density, promote a healthy heart, battle diseases, reduce cholesterol and be used as anti-inflammatory.

Safe and Healthy Fruits For Dogs

Like with vegetables, there are a ton of great fruits for dogs to eat. From personal experience, dogs tend to like fruits better because they have more flavor and a sweet taste to them. Just to name a few, great fruits for dogs include:

Note: You should never feed your dog any grapes or raisins because like onions, they are toxic to your dog. Learn about why they are bad for dogs.

Q/A: Can Dogs Eat Onion Rings?

Can dogs eat onion rings? No, onion rings are just as bad for dogs.

No, dogs cannot eat onion rings. They are, in fact, even worse for your dog than raw onions. Not only do onion rings contain the toxins that can hurt your dog, they are fried. Generally, any fried food is a big NO for dogs to eat.

If fried foods aren’t healthy for humans to consume, they certainly aren’t good for your dogs. If your dog accidentally ate an onion ring that fell on the ground, they may not be in much harm. Still, it’s a good idea to keep an eye on them to see if they display any symptoms listed above.

If your dog ate your whole serving of onion rings, consult with your veterinarian as soon as possible. The above action steps can be used if your dog ingested a significant quantity of onions, as well as onion rings.

In Conclusion: Can Dogs Eat Onions?

Onions can do a lot of damage to your dog because they contain a substance called Thiosulfate, which cannot be properly digested by dogs. Unlike humans, dogs don’t have the proper enzyme to break down Thiosulfate. This means that dogs should not eat onions for any reason.

However, if your dog accidentally gets ahold of a few slices, they may be fine. For cases where the dog consumes a large quantity, there are steps to take. First, you’ll want to induce vomiting to get out any many onion pieces from their stomach. Next, you’ll want to absorb the toxins by giving them activate charcoal. Finally, the visit to the veterinarian is inevitable.

One of the most common concerns of dogs exposed to onion toxicity for a prolonged time is Heinz Body Anemia. Onion toxins can lead to red blood cells in your dog to significantly decrease, thus causing Anemia.

The best thing to do is to try your best to keep onions away from your dog at all cost. When handling onions or foods with onions around dogs, always be extra careful.

The Smart Canine is an online resource dedicated to providing owners with the best and most accurate information on dog care. Our team has thoroughly researched on the topic of Onions and dogs. However, we cannot guarantee that your dog will experience certain side effects and risk from onion consumption. Follow the action steps at your own risk. This is meant to be an informative guide and we always recommend consulting with your local veterinarian.

Armando P Diaz

Sunday 12th of June 2022

Thank you this is very informative and useful for dogs loving owners.

grace Broderson

Friday 6th of August 2021

hi recently my dog Sasha got ahold of 3 or 4 onion rings i was wondering if its bad she ate some chocalte one time actually 3 so is it bad if she ate onion rings?


Friday 2nd of July 2021

I'm a nine-year-old who gave my dog a piece of meat covered in onion juice. This looks helpful.


Friday 6th of September 2019

Dogs shouldn’t be eating avocados, cherries or oranges!

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