Petco Text Logo
Petco Pet Logo

  • Two Easy Ways to Start Earning Rewards!

My dog ate a small piece of onion. Will she be okay or is it toxic?

Updated On September 23rd, 2025

Pet's info: Dog | Maltese | Female | spayed | 1 year and 4 months old | 7 lbs

My 7 lb Maltese ate a piece of diced onion - probably 1 cm in size. Will she be ok?

1 Answer

Most Helpful Answer

Image profile

Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on May 18th, 2018

Consumption of as little as 15-30gm/kg of onion has resulted changes in the blood of dogs who eat it. Onion toxicities are noted in animals that ingest more than 0.5% of their body weight. That would be like a 20 pound dog eating 1/4th of a cup of onions. For Abigail, she would have to ingest around 1/8th of a cup in order to see toxic signs. Given that a 1cm piece of onion isn't enough to make 1/8th of a cup, she should be fine. Just make sure she doesn't get any more! Best of luck, I hope this helps!

Vote icon

12Pet Parents found this answer helpful

Related Questions

Petco Pet Education Center
Health & Wellbeing
My dog ate the tiniest piece of minced onion, will he be okay? Size of piece shown in photo.
The dose of onion in dogs that is toxic is about 0.5 grams per kilogram of body weight. For a 10 pound dog, that would be about 20 grams of onion. There are about 5 grams in each teaspoon, so Marlin would have to eat over 4 tsp of onions in order to be concerned about toxicity. The biggest concern comes with dehydrated onions which are much more concentrated than fresh onions. It sounds like Marlin will be fine, but please contact your veterinarian if you have any concerns. I hope that was helpful! Thanks for using Boop by Petco.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My dog ate a small piece of cooked onion. He is 16lbs. Will he be okay?
Hello. If it was just a one time small piece, he will be fine. A dog this size would have to eat a tablespoon or so of cooked onion to even begin to have any issues. He will be fine. Thanks for using Boop by Petco.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My dog may have eaten a piece or slice of raw onion. He is about 24 pounds. Will he be OK?
It typically takes ingestion of about 0.5% of your pet's body weight of onion to be at risk of onion related toxicity. This calculates out to be approximately 0.15 lbs, or around 2 ounces. Unless your pet ate anything close to that amount or more, it is not recommended to do decontamination for him. With a piece of [onion](https://www.petcoach.co/canigive/dog/onions) that only weighs a few grams I would not be concerned. Just monitor him for the next couple of days for any GI upset, lethargy, panting or pale gums. And if he gets a hold of any more you can always contact the [Pet Poison Helpline](https://www.petpoisonhelpline.com/). There is a charge associated with this call.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My dog got into my onion rings she is part coonhound part Australian shepherd and weights about 50 pounds. She ate about 7 or so onion rings and there are no vets opened or taking new clients in the town I live in cause of covid 19
Hello and thank you for contacting Boop by Petco. Onion in toxic to dogs but it does not sound that Dakota has eaten large enough amount of onions to develop intoxication. The toxic dose of onion is about 15-20g/kg of bodyweight, so it means that Dakota would have to eat about 300-400 grams of onion (which is a whole large onion) to get into trouble. Please, keep an eye on her at home, she may develop mild signs of gastroenteritis (one vomit, mild diarrhea etc) but there should not be any other worrying symptoms.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My 16 lb. dog ate a few small slices of onion (I think) from a McDonald’s hamburger. Knowing onions are toxic but given the small amount will he be ok?
Hello. You have nothing to worry about with this small amount of cooked onion. The problems associated with ingesting onions usually occur with chronic, long term ingestion possibly from a bored dog eating onion grass outdoors or home cooking for a pet & an owner not realizing that onions may cause problems . An occasional bite will never cause a problem. All will be fine. Thanks for using Boop by Petco.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My dog weighs over 100 pounds and he ate a small amount of onions earlier today. He ate his dinner and is drinking water, but I'm still worried. Will he be okay?
Onions contain an ingredient called thiosulphate which is toxic to cats and dogs. The ingestion of onions causes a condition called hemolytic anemia, which is characterized by damage to the red blood cells. Onion toxicity can cause the red blood cells circulating through your pet’s body to burst. Symptoms of this condition include breathlessness, lethargy, diarrhea and vomiting. Your pet also could lose interest in food as a result of this type of poisoning. It may take up to two to four days after your pet eats the onion for symptoms to appear. All onions — whether cooked or raw — are a danger to your pet. It takes a very small amount of onions to poison your cat or dog. Consumption of as little as 15 to 30 g/kg in dogs has resulted in clinically important hematologic changes. Onion toxicosis is consistently noted in animals that ingest more than 0.5% of their body weight in onions at one time. At 110 pounds, Holmes would have needed to ingest 750-1500 grams of onions to show toxi
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My 2 yr old Labrador is approx 27kg and has eaten approx a teaspoon of cooked onion. Is that enough to harm him?
Hi there and thank you for using Pet Coach! The amount of onion and the size of Paddy should not cause any clinical symptoms associated with toxicity. You may see GI signs such as vomiting / diarrhea. I would monitor for now and if you notice any signs such as lethargy, inappetance, vomiting blood, etc., I would have a veterinarian examine Paddy and test her blood. I hope this helps! Please let me know if you have any other questions / concerns. I am also available via consultation if needed.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My dog just ate a onion in a small quantity ... She's a small german shepherd mix .. It's 3:45 AM Here and no 24/7 Clinic available nearby.. WHAT SHOULD I DO? Should I take her to a clinic now or should I wait till daytime?
Oh no, that wasn't good that Akamaru ate onions! It can take as little as 15 to 30 g/kg to cause toxicity in her. I'm not sure how much she weighs, but if it was a small quantity and she's is likely a large dog being a GSD, a small quantity won't do any damages. I would have her seen by a vet in the morning to be safe, however, but you can always take her into a clinic now to be sure she is ok.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
my dog ate a couple pieces of fried onion petals, she weighs about 100 pounds, will she be okay ??
A few pieces of onion ingested by a dog of Mochi's size will likely cause nothing worse than some minor stomach upset, if anything at all. She would need to eat 2 or 3 med/large onions in order to be at risk of serious toxicity. If she develops vomiting or diarrhea but continues to behave normally, you can fast her for 24 hours then feed a bland diet in small, frequent amounts until symptoms resolve. Transition slowly to her regular diet afterwards.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My 50lb Mountain Cur grabbed and ate half a veggie burger sub off the table. It had a tomato slice, small amount of onion slices
That's not good that Roxxi ate the sub with onion slices! Tomato isn't toxic to dogs, but onions are toxic. The toxic dose is typically 15-30 grams per kg of body weight. At 50lb, she is 22.72kg, and that means she would have to eat between 341-682g of onion to cause any toxic effects. A small amount of onion slices would likely not weigh that much, so I imagine she will be fine. I hope this helps!
Updated on September 24th, 2025

Related Searches

Dog Food Dog Supplies Dog Health & Wellness Dog Food With Grain Wet Dog Food Small Breed Dog Food Dry Dog Food Dog Vitamins & Supplements Premium Dog Food Electrolytes for Dogs Canine Aspirin Canine Aspirin Dog First Aid & Recovery Canine Aspirin Dog Health & Wellness DOG by Dr Lisa Canine Aspirin Dog Pain Medicine & Relief PetAlive Sensitive Stomach Dog Food Onsior Dog Medicine and Prescriptions Canine Aspirin Dog Supplies Onsior Dog Pain Relief & Arthritis Meds Purina ONE Small Breed Dog Food
image
Have A Vet Question?

Book an appointment with the pros – our expert vets are here to help.

Book Now

Sponsored