My Dog Ate Onion – What Now?

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onionsThere are many kinds of food that humans eat which are unsafe for dogs. Onions are not an exception. Feeding your pooch onions can make him seriously ill, whether they are raw, cooked, or in powdered form.

What you Need to Know

Onions are toxic to canines because of the substance they contain known as thiosulfate. Since dogs do not have the enzyme used to digest this substance, onions become a harmful food for them. Although rarely any observable side effects can be seen if your pooch consumes just a minimal amount of onions. For example, he sneaks a piece of pizza off the counter or steals a bite of your burger, most likely he will be just fine. Too frequent feeding of onions, however, can affect your pet’s health and vitality. Additionally, onions contain a compound called organosulfur that results in toxicosi, a condition brought about by poisoning which can be easily absorbed by the dog’s digestive tract.

Onion ingestion commonly leads to liver damage, asthmatic attacks, allergic reactions, weakness, diarrhea, discolored urine, anemia, vomiting, and even dermatitis.

Onions and Heinz Body Anemia

One of the most critical problems that arises from onion toxicity is canine Heinz Body Anemia, also referred to as Hemolytic anemia. It is a condition that is brought about by the destruction of the dog’s red blood cells that leads to a decrease in red blood cell count; thus, causing anemia.

Symptoms vary depending on the amount of onions the dog has consumed, his size, and the time period for which they have been ingested. It is notable that consuming a large amount of onion in a single sitting is less dangerous that consuming a very small amount over a length of time. Remember this if you’re someone that feeds your dog from the table. Many of the foods we eat contain at least a small amount of onion or onion powder. Read your labels carefully and avoid feeding these foods to your dog.

Common warning signs for Heinz Body Anemia include pale mucous membranes like the gums, brownish or reddish urine color, rapid heart and/or respiratory rate, weakness, and depression. Vomiting, diarrhea, and loss of appetite may also be observed.

What to Do when Your Dog Ingests Onions

It is important that you immediately consult your vet if symptoms occur as a result of onion ingestion. 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. Bathing and drying your dog may also be necessary in cases of skin infection.

Other treatment options include maintaining the dog’s hydration by providing fluid in his bloodstream, applying therapy for liver damage, and calling for blood transfusions if necessary.


  1. We have a Jack Russell Terrier that we have had since she was a year old. She is 11 years old now. She is my wife’s service animal (seizure response dog). I have fed her table food for as long as we have had her, she eats what ever I do. I love my onion and garlic so she has had quit a bit of it as long as we have had her. We would never do anything to harm her but didn’t know about the onion thing until this year. I try not to give her any actual onion pieces now but I still use onion to season with and she does get an occasional piece in some foods. She weighs 14 pounds and has never had any medical problems. She’s a active as any 11 year old if not more and has never had ant medical problems. I’m beginning to think all this is a big scare tactic or a way to make money for vets.

    • Right, Charles; and many people smoked cigarettes while pouring gasoline out of a can, and never set themselves on fire. Others weren’t so lucky, and were severely, even fatally, burned.
      Some years back, it was found that onion powder in meat baby foods (fed to infirm cats while they were under vet care) was found to cause hemolytic anemia. (Major baby food brands don’t use onion powder anymore.)
      But if you think it’s “a big scare tactic or a way to make money for vets,” just go on doing whatever you think is right for your dog. You probably won’t post back here if some day you find out the hard way that you were wrong. It’s too bad the faithful dog would have to suffer because you think you know more than veterinarians do.

      • You are right. Our dog is in the vet right now pinned with dextrose. He ate onions and garlic from scrap last week and I still have to tell the vet 1st thing tomorro morning about what I just read. The symptoms are exactly the same as in the article.

    • maybe cooked onion or in very small amounts is okay? not sure, but this is definitely not a scare tactic. my friend’s dog got a hold of some raw onion and started vomiting and became very ill. he is now in the ER! please be careful!

  2. Does anyone ever answer anyone’s questions here at all?????!!!!!

    I have really screwed up this time….. I gave our precious little Chihuahua quite a bit of onion tonight. I could just shoot myself now! She had about 3/4 cup of Rice-@-Roni with burger and a lot of diced onion added in it. If I’ve hurt her, I’ll never forgive myself…… I will call the Vet in the AM, but I sure wish there was someone here who answered these questions!!
    See, our Vet told me that onion was poisonous to dogs, and I gave it to her anyway. I don’t like myself very much at all right now……. :(

    • I think this comment section here is just for making comments, not for asking questions. There’s nothing on this site that says there’s someone here who’ll answer questions if we post them in this comment section.

    • Kathy,
      I am not sure what to have told you at that time nor can I tell you now. All I need to know is how is your dog, did you have to do anything for her? I am asking because I dropped as smaller piece of onion and my 4 pound chihuahua got it. I am not feeling so good about it either.


  3. My small 6lbs 10 year chihuahua ate a small piece of cooked onion that fell on the ground when my mom was cooking. My mom noticed her walk away with it but got away with eating a bit. I’m so scared I don’t know what to do. She burped (she burps all the time) and I smelt the onion. I’m so scared someone please help me! If something happens I don’t know what I’ll do!