Can Dogs Eat Onions?

Can Dogs Eat Onions

With all of the fruits and veggies that are great for dogs, you may be wondering if dogs can eat onions. Is it dangerous to share your burgers, soups, and tacos with them? 

It can definitely be dangerous for your dog if these foods contain onions. Here’s what you need to know … 

With all of the fruits and veggies that are great for dogs, you may be wondering if dogs can eat onions. Is it dangerous to share your burgers, soups, and tacos with them? 

It can definitely be dangerous for your dog if these foods contain onions. Here’s what you need to know … 

Are Onions Really Toxic?

People eat onions all the time. We mix them into food and sauces. How can humans eat onions with no real issues but yet, onions are toxic to dogs?

Here’s why. Onions contain N-propyl disulfide. Relatively harmless to humans, this compound can lead to the breakdown of red blood cells in dogs. This breakdown can cause hemolytic anemia  … also called Heinz body anemia.

Hemolytic anemia tricks your dog’s immune system into thinking red blood cells are invaders. The immune system attacks these “invaders” and destroys red blood cells. This affects your dog’s red blood cells’ ability to transport oxygen. Severe hemolytic anemia can be life-threatening, so you need to try to keep your dog away from onions! 

All parts of the onion are toxic. As are most of the allium family of vegetables … except for garlic (I’ll come back to garlic later). The allium family of veggies includes:

  • Garlic
  • Onions 
  • Leeks 
  • Chives
  • Scallions 
  • Shallots

Not only should you try to avoid giving your dog onions … but you should also try to avoid foods that use onion products. Onion powders and dehydrated onions are also toxic. Onion powder in particular is in everything from soup to baby food. They’re not as potent as raw onions but in large enough quantities, they could cause your dog harm. 

One research study shows that some manufacturers may add powdered onion to their canned dog food so always read ingredients very carefully.

Even if you don’t intend to feed your dog onions, he may find them in other ways. If your dog gets into the garbage, compost or vegetable garden for example. 

How Much Onion Is Toxic To Dogs?

Onion toxicity can occur if your dog eats approximately 0.5% of his weight. For bigger dogs, this might seem like a lot but for a smaller dog, it doesn’t take much. For example, ¾ of a cup of onions is enough to make a 75 lb dog sick. ¼ of a cup can cause onion toxicity in a 25 lb dog. For a 10 lbs dog, 1½ tablespoons is enough to do damage. 

If You Know Your Dog Ate Onions

If you realize that your dog has wolfed down some onions, you should speak to your holistic vet right away about what to do. 

Depending on when your dog ate the onions, the approach will differ. If your dog has just eaten the onions, your vet may recommend you induce vomiting to try and get the onion out of his system. Sometimes you can induce vomiting at home using hydrogen peroxide. Other times your vet may prefer to use emetic drugs that cause vomiting.

Your vet may also suggest giving your dog activated charcoal.

Holistic veterinarian Patricia Jordan DVM recommends you always have TOXIBAN activated charcoal in your first-aid kit. But you can also buy activated charcoal in capsules from a health store. Activated charcoal can help absorb toxins from the gastrointestinal tract. But this will only work within a short time after your dog eats the onions. Once they’re fully digested, it’s too late. 

Symptoms Of Onion Toxicity

Your dog may get into onions without you realizing it … so recognizing the symptoms of onion toxicity is very important. Symptoms may even occur days after he ate the onions. Symptoms like these can be cause for alarm: 

  • Decreased appetite
  • Weakness
  • Lethargy
  • Fainting
  • Pale gums
  • Diarrhea
  • Problems with balance and movement
  • Elevated heart rate
  • Discolored urine

You may not know if your dog has eaten onions. But if he starts exhibiting one or more of these symptoms, you should contact your veterinarian immediately. They could be a sign of severe illness. 

When You Go To Your Vet

In more serious cases when anemia has begun, your vet will likely give your dog IV fluids. She will also look to treat any liver damage that may have occurred. A blood transfusion may be required for very serious cases. Sometimes your dog may need supplemental oxygen. 

Even when you take your dog home, you will have to monitor him for additional anemia symptoms. 

Note: You might have to take your dog to a conventional veterinarian for this treatment. But keep in touch with your holistic veterinarian. She will be able to help you once your dog gets home, using more natural remedies to support his recovery. 

RELATED: How to work with your vet: Agree to disagree …

Is Garlic Also Toxic?

If you look up “are onions bad for dogs?” you will often see garlic lumped in with onions. While they’re part of the same family, garlic is not toxic to dogs … if you use fresh, raw garlic and give the right amount for your dog’s size.

A lot of the confusion comes from one study in particular. During the study, the dogs were fed 5 grams of garlic per kilo per day. This did cause an adverse effect but it was also a huge amount of garlic. 

To get a similar result you’d have to feed 4 full heads of garlic (approximately 60 cloves) to a 75 lb dog or 23 grams of garlic (6 to 8 cloves) for a 10 lb dog. That’s a huge amount of garlic!

But in small amounts, garlic can be good for your dog’s health. It can help with:

  • Widening blood vessels. This allows blood to flow and lowers blood pressure.
  • Preventing blood clots.
  • Stimulating the lymphatic system to remove waste.
  • Decreasing cholesterol build-up.
  • Preventing tumors.

Garlic also has antibiotic, antifungal and antiparasitic properties. And it’s useful in repelling ticks and fleas. 

That’s not to say you shouldn’t use some caution. Don’t give garlic to puppies under 6 months and be very cautious feeding garlic to pregnant dogs. It’s best to ask your holistic vet before giving it to a pregnant dog.

RELATED: Can dogs eat garlic? The bottom line …

The Final Verdict

A small piece of onion won’t hurt your dog but it doesn’t take much to put your dog in peril. If your dog steals your leftovers, or gets into garbage or compost that may contain onions, talk to your holistic vet right away and watch for symptoms of onion toxicity.

The sooner you can treat it, the sooner your dog will be back to his healthy self.


Harvey JW, Rackear D. Experimental Onion-Induced Hemolytic Anemia in DogsSage Journals. 1985, July 1.

Kovalkovičová N, Šutiaková I, Pistl J, Šutiak V. Some food toxic for petsInterdiscip Toxicol. 2009 Sep: 169-76. 

Beynen AC. Onion in canned dog foodResearchGate. May 2020.

Lee KW, Yamato O, Tajima M, Kuraoka M, Omae S, Maede Y. Hematologic changes associated with the appearance of eccentrocytes after intragastric administration of garlic extract to dogsAmerican Journal of Veterinary Research. 2000 Nov;61(11):1446-50.

Houston DM, Myers SL. A review of Heinz-body anemia in the dog induced by toxins. Vet Hum Toxicol. 1993 Apr;35(2):158-61. PMID: 8470361.

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