Food Guidelines

My Dog Ate Onion – What Now?

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. Bob

    Feb 10, 2017 at 3:54 pm

    1/2 cup milk 2 Table spoons Hydrogen Peroxide….let them drink about half of it.

    My Greyhound just ate 1/2 a cooked medium sized onion left on the counter from chicken soup. (that's half the size of your fist) Thanks to this thread, I used 1/2 cup of milk and 2 Tbs of Hydrogen Peroxide…she drank 1/3 and it induced vomiting within 2 minutes. Went trough 10 catch-bowels but the onion came up -ALL of it. Less than 20 minutes.

    There was some digestional irritation for a few hours but it worked!!!

    Thank You.

    Bob and Sage in Wells Maine

    1 cup for a 60lb dog is OVERKILL….

  2. Rahul

    May 22, 2016 at 5:14 am

    Do dog eat grass as well?

    • PATTI

      Oct 2, 2016 at 11:13 pm

      Grass is normal though the dog may still vomit some up.
      Onions are a big issue. My little dog has discovered how to get up onto the kitchen counter. If salad bowls with salad residue are left unattended, he will try to lick them off. It cost me $1,000.00 the one and only time he got into the salad bowls. I think I have got to start eating food with out any onion to help him stay safe.

      • Patrcik

        Oct 7, 2016 at 6:19 pm

        My basset hound ate and onion from Burger King he just ate one is he gang to get sick or will he throw up?

    • Ethan russell

      Oct 7, 2016 at 9:08 pm

      My dog just a a sliver of onion will this affect her if it does how much does it cost to treat her

  3. Bob Ross

    Apr 9, 2016 at 12:57 pm

    Take her to an ER vet. Will make you feel better and just MIGHT save her life.

    • Nemo

      May 23, 2016 at 4:28 pm

      What’s wrong with onions and garlic?
      When my mother was growing up in Mexico the maids gave their dog onions and garlic every day and that dog lived for 14 years. Everybody did that. Dogs ate leftovers, even onions and garlic, and they were fine. ??

      • Anna

        Oct 8, 2016 at 8:50 am

        What’s wrong with it you’ll find out if you read the aricle.

        • Margaret Gibson

          Nov 12, 2016 at 3:58 pm

          My dog had some left over stew yesterday I forgot about the onion in it could I worm him out as not eaten anything today don’t think he well its the weekend and my vet sit until Monday but not even been sick but he constipated

        • Sarah B.

          Nov 30, 2016 at 9:45 pm

          I just wanted to add that garlic, onions, leeks and green onions are all toxic to dogs and cats. So watch those relish platters and all holiday food out of the mouths of all animals. Also remember grapes and chocolate will poison them too! It’s safer to put your pets in a closed room with food and water and maybe leave a TV or radio so they aren’t listening in to every detail going on in the rest of the house. It is too difficult to keep your eyes on your guests, food and pets at the same time. Make this a safe holiday!

  4. Ida9464

    Feb 9, 2016 at 2:04 pm

    Onions and garlic do the same thing. Even in tiny amounts, they cause red blood cell lysis aka hemolysis aka hemolytic anemia if they get either a lot at one time or a little bit frequently. I know there is question of if garlic is bad but the fact is, they cause lysis of red blood cells and it takes awhile for spleen to make more. Period. Why would you take the chance? Ok I don’t want to argue about that. My little Maltese got two of my 1000 mg garlic gel caps Thursday. Today is Tuesday. So my ten pounder ate 2000 mg of this. I gave one tsp aka 4-5 ml of hydrogen peroxide 3 percent via syringe. Then I repeated after 15 minutes. She vomited twice but I couldn’t see gel cap but it probably dissolved in four minutes because that’s what happened in my mouth. Later I read one half tsp per ten pounds but maximum of three tsp for large dog. You may repeat one time as hydrogen peroxide has toxic problems on it’s own. Called vet next morning, watch dog. She was fine till this am, tired with vomiting. Read up on this and learn from my stupidity. It may take days to see effects.

  5. Jimi

    Jan 22, 2016 at 12:43 pm

    those having emergency should consult vet instead of wasting time here!

    • Brandy Arnold

      Brandy Arnold

      Jan 22, 2016 at 1:16 pm

      Perhaps they’re hear to find out IF it’s an emergency…

  6. FINCH

    Dec 19, 2015 at 2:20 am

    A Long eaten Onion dog can she still survived it?Pls pals help

  7. michael leahy

    Dec 12, 2015 at 11:49 pm

    Its pathetic that no one on here told these people the quick and sure solution. IF YOUR DOG EATS ANYTHING TOXIC, MIX MILK AND ABOUT A CUP [ for a 60 pound dog] OF HYDROGEN PEROXIDE AND GIVE IT TO YOUR DOG. You have about 45 minutes to do this. You should do it right away though.

    This is the solution.


    • Bobbie

      Dec 15, 2015 at 5:07 pm

      YES Michael! Thanks for posting this! I knew this, but it’s been a while since I had to do it. My dog ate cooked onion I threw out of the crock pot. I went online as a reminder and saw this. I gave him the 3 percent hydrogen peroxide(the normal hydrogen peroxide kept for cuts, etc. A reminder for people NOT to use stronger-the kind for hair colouring! This can cause damage). But, gave him about 8 teaspoons as he is around 80 lbs. I recall it is recommended approx. 1 teaspoon per 10 pounds. Walked him around calmly on a leash. He just threw up the onion after about 20 minutes. It looks like it all came up! This is a life saver! Thanks again for posting on here!!!

    • JoAnne

      Jan 6, 2016 at 9:00 pm

      Yep, or just hydrogen peroxide did the trick today (will depend on dogs weight). My 42 pound took 1 TBSP

    • Robert

      Jan 3, 2017 at 2:44 pm

      This is insane. Do not drink oxidizing agents. Even 3% hydrogen peroxide is dangerous. If doctors no longer recommend putting it externally on a cut, then why would you consider DRINKING it? Of course it’ll make you throw up, it’s oxidizing your stomach lining.

  8. Charles

    May 16, 2015 at 12:18 pm

    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.

    • Doug

      Jul 19, 2015 at 1:14 pm

      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.

      • hermes

        Nov 24, 2015 at 9:25 am

        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.

      • Bob Ross

        Apr 9, 2016 at 12:53 pm

        Some idiots do NOT deserve the ownership loyalty and friendship given from an animal that trusts his or her LIFE to your stupidity.

    • greg

      Aug 17, 2015 at 12:48 pm

      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!

    • Chicken Wangs

      Feb 24, 2016 at 9:26 am

      don’t you think vets would be telling us to fed onions to them so that you have to bring them in? telling us not to is avoiding going to the vet. are you retarded?

    • kierston

      Jul 18, 2016 at 6:16 pm

      you are lucky my dog wont eat because of eating onions.

  9. Kathy Greer-Gregory

    Feb 16, 2015 at 6:58 am

    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……. 🙁

    • Kathy Greer-Gregory

      Feb 16, 2015 at 12:09 pm

      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.

    • Warren

      Apr 17, 2015 at 12:20 am

      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.


  10. sam r

    Dec 2, 2014 at 11:31 pm

    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!

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