Are Green Onions Safe for Dogs?
Veterinary toxicology authorities consistently classify green onions as toxic to dogs. Green onions, also known as scallions or spring onions, are members of the Allium family, which includes onions, garlic, leeks, and chives.
The ASPCA and Pet Poison Helpline list onions in all forms as poisonous to dogs. The AKC explicitly includes green onions in this classification, noting that they pose the same risks as other onion varieties.
Across veterinary references, green onions are not considered safe in any form.
Why Green Onions Are Dangerous for Dogs
Toxic compounds
Veterinary toxicology sources identify thiosulfates and related sulfur-containing compounds in onions as the cause of toxicity. These compounds damage red blood cells in dogs.
Effect of cooking or drying
Pet Poison Helpline and the AKC state that cooking, drying, or chopping green onions does not reduce their toxicity. Raw and cooked forms are treated the same in veterinary guidance.
Cumulative exposure
Veterinary sources note that onion toxicity can occur after a single larger exposure or from repeated smaller exposures over time.
Signs Reported in Green Onion Toxicity
Veterinary organisations report the following signs associated with onion ingestion:
- Vomiting
- Diarrhoea
- Lethargy
- Weakness
More serious signs
- Pale gums
- Rapid heart rate
- Collapse
- Signs consistent with haemolytic anaemia
Symptoms may be delayed and can appear several days after ingestion.
Ingredients or Additives to Watch For
Green onions commonly appear in foods discussed in veterinary warnings:
- ❌ Seasoning blends and garnishes, often added after cooking
- ❌ Soups, sauces, and stir-fries, where green onions may be mixed in
- ❌ Dehydrated green onion flakes or powders, which remain toxic
Veterinary sources treat all forms as unsafe.
Puppies vs. Adult Dogs
Veterinary toxicology sources state that green onion toxicity affects dogs of all ages. Puppies may be more vulnerable due to smaller body size, but adult dogs are also at risk.
Other Onion-Based Foods Classified as Toxic
Cooked onions
Cooking does not make onions safe, according to veterinary sources.
Onion powder
Veterinary organisations highlight powdered forms as particularly dangerous due to concentration.
Leeks and chives
These Allium relatives are also listed as toxic.
Allium Plants Listed as Toxic
Veterinary and pet-safety organisations consistently include:
- Green onions (scallions)
- Onions
- Garlic
- Leeks
- Chives
- Shallots
All are classified as toxic to dogs.
Frequently Asked Questions (FAQ)
This FAQ summarises themes appearing in veterinary toxicology and pet-safety resources.
It is informational only and not a substitute for professional veterinary care.
Are green onions different from regular onions?
Veterinary sources state that green onions are a type of onion and pose the same toxic risk.
Does cooking green onions make them safe?
Veterinary organisations confirm that cooking does not remove onion toxicity.
Can small amounts be harmful?
Pet Poison Helpline notes that repeated small exposures may still lead to poisoning.
Source Reference
This page compiles information from publicly accessible veterinary and pet-safety resources, including:
-
ASPCA Animal Poison Control — “Onion”
https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/onion -
Pet Poison Helpline — “Onion Poisoning in Dogs”
https://www.petpoisonhelpline.com/poison/onion/ -
American Kennel Club (AKC) — “Can Dogs Eat Green Onions?”
https://www.akc.org/expert-advice/nutrition/can-dogs-eat-green-onions/
This page is informational only and does not constitute veterinary or medical advice. Readers are encouraged to review the cited sources directly.
