My Big Onion Scare

Kilo the Pug says Onions are toxic

Last Friday, I bought 2 cheese and ham quiches from a local gourmet store, as I do quite regularly. I took one up north and left one in the fridge for my daughter. Unfortunately, the store may have mislabelled these 2 quiches. They were onion and tomato, not my usual ham and cheese. My daughter can not eat onions or tomatoes, so she had a bite, tossed her slice, and left the rest.

These quiches are made at the store. I was angry because I felt this showed a lapse in food safety. If the labels on quiches were misleading, what about the cookies and other prepared foods for those people (or dogs) with severe allergies or intolerances. Plus it was a waste of money.

On Tuesday, I took the remaining quiche out of the fridge to return. I put it in a plastic bag and left it by the front door while I grabbed my purse. I headed out to do some chores and the quiche stayed by the door. I only realized it was not with me when I finally got to the store. It was up on a shelf but Kilo the Ninja Pug must have jumped up and pulled on the ends of the white plastic bag until it fell. He then tore open all the packaging and ate the whole piece.

I came home to a guilty, but very satisfied looking Pug licking his lips 2 hours later. At first, I was just a little annoyed he had eaten the evidence and made a mess. Then I remembered why I was returning the quiche – ONIONS.

Fried onions

I knew onions were not great for dogs,  so I googled “What if My Dog Eats Onions?” and came across Onions the Secret Killer by Dr Sophia Yin. I was terrified. I called my vet and asked him to stand by in case we needed to make Kilo sick and give him charcoal. I then called the ASPCA hotline (I had spoken to them when I did a recent post on Poisonous Plants).  They were fantastic. They asked Kilo’s weight (18lbs) , age (nearly 3) and other details. Then they asked how much he had eaten when. We estimated around a tablespoon or 15 grams  2 hours earlier (I called the store to ask and they were very unhelpful).

The Vet at ASPCA advised that I wait and see. They felt that it was too late to make him sick and that going to my vet and giving him charcoal could have other risks without enough benefits.   While any amount of onion is toxic,  they did not feel that this amount would cause him terrible damage. They suggested that I take him for blood tests if he showed any symptoms after 2-4 days. My Vet agreed with their recommendation,  so we are waiting. Luckily Kilo just had a check up a few weeks ago with blood tests so we have a base.

So far so good. He seems normal. If Kilo shows symptoms today or tomorrow, and his blood work is bad, he might need hydration or even a transfusion.

Why Onions Are Toxic

Thiosulfate found in onions is toxic to canines because they do not have the enzyme to digest this substance. Additionally onions contain a compound called organosulfur that results in toxicosis.

According to the ASPCA, significant onion ingestion may lead to liver damage, asthmatic attacks, allergic reactions, weakness, diarrhea, discolored urine, anemia, vomiting, and even dermatitis.

One of the most critical problems that can arise from onion toxicity is canine Heinz Body Anemia or Hemolytic Anemia. Toxicity results because an oxygen-transporting protein called hemoglobin in the red blood cells gets oxidized. The  hemoglobin forms clumps which can’t carry oxygen as well. These small clumps, called Heinz bodies, can be seen in the red blood cells under a microscope.

Blanco the rescue dog

Onions and Heinz Body Anemia

Heinz bodies don’t usually cause life-threatening problems themselves; the red blood cells can still carry oxygen, just not as efficiently. Heinz bodies cause problems by decreasing the red blood cell lifespan. As a result, the dog may become anemic. If a dog eats a large amount of onions, the dog may develop a sudden anemia 2-4 days later. So scary.


■Pale or icteric mucous membranes like the gums

■ Weakness, depression

■ Rapid heart and respiration rates (caused by hypoxia)

■ Vomiting, anorexia, and/or diarrhea

■ Onion odor on breath

■ Brownish or reddish urine color

■ Loss of appetite

Read more about Onion Toxictiy from the ASPCA

So far, Day 3, Kilo has not shown any symptoms at all. I delayed a trip to monitor.

Jackson-Springer Doodle

Toxic Doses

According to the ASPCA’s, “Toxology Brief: Onion Breath” article in Veterinary Technician, an early study (“Onion Toxicity In A Dog” published in Mod Vet Pract) revealed onion toxicity occurs in dogs when the amount of onions fed was more than 0.5% of the animal’s weight.

A review of the ASPCA Animal Poison Control Center case record database for Allium cepa exposure over a 2-year period revealed 23 cases (20 dogs, 3 cats). Six of the affected dogs and one cat showed clinical signs. The data revealed that it takes a fairly large amount of ingested onions before signs are observed but that the dose in the reported cases was consistently over 0.5% of the animal’s body weight.

Dr Yin estimated that 1/4 of a cup can make a smaller 20-pound dog like Kilo sick, while several cups may be needed to make a large dog sick. Cats are even more sensitive.

According to Dogster, onion toxicity builds up over time – so if the dog is getting a little bit of onion every day – it could build up in his system over time and have toxic effects.

What to Do when Your Dog Ingests Onions

PetMD urges you immediately consult your vet if your dog ingests onion, or if you see the symptoms listed above.

I called the ASPCA Hotline as well as my Vet and they were both fantastic – I paid US$65 happily.

24-hour ASPCA emergency poison hotline 1-888-426-4435 (fees may apply).

If caught within 2-3 hours, Treatment normally involves inducement of vomiting, carrying out gastric lavage or flushing out the stomach, and making use of activated charcoal to treat not just poisoning but allergic reactions as well.

They may take blood tests immediately then 2 days and 4 days after ingestion to check for anemia, if the dog shows symptoms.

Be careful to maintain your dog’s hydration levels, your vet may do this by providing fluid in his bloodstream. Furthermore your vet may have to assess for liver damage and may do blood transfusions if necessary.

Did You know? Garlic, of the family Liliaceae, is related to onions and has similar chemical characteristics.

black puppy being held looking away

Conclusion- Pet Safety

Ingesting onions, whether they are raw, cooked, or in powdered form can make a dog (or cat) seriously ill.  However, dogs’ red blood cells do regenerate. With proper supportive care, a dog should make a full recovery – usually in 10 to 14 days.

Many human foods contain at least a small amount of onion or onion powder. To be safe, always read your labels carefully and keep human food out of reach where possible.

According to PetMD’s “How to Safely Feed Your Pet People Food“, when it comes to foods like grapes, raisins, macadamia nuts, chocolate, onions and garlic, it’s best to just stay away.

Stay Safe! Read Dogster’s list of vegetables that aren’t safe for dogs.

Pet Safety Month

Photo credits for Blog Paws Badge:

(1) CJ Jackson; (2) Christine Paul; (3) TattleCat; (4) Ann Staub

Poor little Kilo is keeping quiet and well hydrated for the next few days. Then we’ll get back to our fitness routine.



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  • Yikes, that was a scare. Hope he is okay and thanks for the info.

  • I am so glad Kilo is alright, that is scary stuff, thank you for sharing about onions, a number of people don’t know they are toxic.

  • Always best to err on the side of caution. I am reluctant to give garlic as recommended to keep fleas at bay for this very reason.

    I hope Kilo feels better soon x

  • Very important info. One of my dogs ate part of an onion once and scared me to no end. She was OK thankfully.

  • Argh, how frightening. I’m so glad Kilo is ok, and I hope he feels better soon.

  • It is scary when we eat something we shouldn’t. I think it really also depends on the dog how they react. Mom had a lab/newf mix that at a bowl of chocolate candy with no problems, we have eaten some onion here and there with nothing happening, but one never knows and the waiting is the hardest part. Glad Kilo seems to be alright.

  • Great information. I knew onions were bad for dogs, but didn’t know why. I sure hope Kilo is ok!

  • Dogs eat the darnedest things sometimes. We like chocolate, even though we aren’t supposed to eat it.

    • Profile photo of Talent Hounds

      Yes Kilo had his stomach pumped and charcoal for a tray of chocolate his first week with us. I think maybe overkill but he was small and he gobbled a lot of bad nuts and dark choc. Now we seem like terrible parents but he is the artful dodger.

  • I’m so glad that Kilo is okay! How terrifying! I would have been a nervous wreck. It is very interesting to know what it is that onions do in a dog’s system (actually cats can’t have onions either). I hope that Kilo’s bloodwork shows that he is fine.

  • Awww, what a scary experience-I hope Kilo continues to stay well! The information you gathered, the hotline number, the process you followed, is extremely helpful – and thank you for sharing it all with your readers!

  • Great article! I’ve often wondered the technicalities behind the toxicity of onions! I’m so glad Kilo is ok, but thank for reminding us of this silent deadly killer!

  • Heather 2 years ago

    I am terrified of feeding Chuleta something that may have onions in it! I know it may be large doses that hurt dogs, but even onion powder I avoid. It’s tough knowing that she really only eats human food. I hope your pup is okay! Great post!

  • That is scary. We’ve had to start keeping our kitchen counters clear of food, because 2 of our dogs can reach up there and help themselves. So far we’ve had a chicken bone scare (2x) and a chocolate cake scare.

    Hope your pup is still doing well.

    • Profile photo of Talent Hounds

      Honestly – Kilo is worse than a toddler as we all absolutely adore him and want to protect him, but he is sneaky, greedy and nimble. He can jump like a basketball player and clear many a counter or table.XS

  • Pulled it down huh? Ohboy. I am glad that so far so good. It sounds scary!

    • Profile photo of Talent Hounds

      I need to talk to our trainer friends on how to break his garbage and counter surfung habits. He clearly feels rewards or disappointmen are worth it?

  • Wow! I am so glad your dog is okay! That is really scary!

  • Fingers crossed for Kilo! Our foster dog was like that… he was a mini vacuum cleaner.

  • So many people toss their dogs any old leftovers and think it’s okay! Good on you for double checking with your vet.

  • What a scare indeed! It’s so easy to unintentionally leave human food out and have the dog help himself. We have a friend staying with us for a few weeks, and I’ve had to tell him to always put away any food right after he’s done eating it, and have also given him a lecture of which foods are dangerous/toxic for dogs. He really listened and is meticulous about putting his food away!
    It was interesting reading about your ASPCA Poison Hotline experience ~ I have mentioned it several times in blog posts, but have never had to call them myself. I’m very glad to read that Kilo seems to be doing well.

  • Onions are scary for pets just by the sheer number of foods they’re in; such important information for all pet owners to know. So glad that Kilo is alright, what a scare.

  • I’m really glad that Kilo is doing well so far and not showing any symptoms of toxicity. I hope he continues to do well.

  • So scary! There are onlinons in LOTS of things that we people eat, and might absentmindedly share with (or leave out for them to swipe when we’re not looking) our dogs. Glad Pug seems to have escaped a medical emergency!

  • Wow, how scary! I am so glad that Kilo was ok. I am disappointed that the store was not more helpful. Onions are not something that I have been really strict about, but now, I am completely changing my perspective.

  • How awful, you must have been terrified walking through the door and finding that Kilo ate those onions. I hope you never go back to that store, they didn’t seem at all understanding. We always have to be aware of cooked food that can contain onion and other potentially toxic foods, especially around holiday time when guests may not know what foods can be toxic to your pet. Thanks for a great post, I hope Kilo doesn’t have any negative effects from this!
    Love & Biscuits,
    Dogs Luv Us and We Luv Them