Can dogs eat onion?
No. Onion is toxic to dogs in every form: raw, cooked, dried or powdered. It damages red blood cells and can cause anaemia, with signs often appearing only days later. Powders and soup mixes count too.
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Why
It belongs to the allium family (onion, garlic, leek, chives), which is toxic to dogs. These plants contain compounds that damage red blood cells and can lead to anaemia. All parts and all forms are harmful: raw, cooked, dried and powdered. Stomach upset can happen with any amount; larger amounts damage the blood.
Signs to watch for
- Vomiting and diarrhoea
- Eating less than usual
- Tummy upset, even after small amounts
- Signs of anaemia (damaged red blood cells), usually a few days later
What to do
Contact your vet or a pet poison helpline right away. Note what was eaten (onion) and roughly how much. Don't wait for signs: damage to the blood usually shows only a few days later.
24-hour help by country →Questions and answers
Is it safe when cooked or as powder?
No. Raw, cooked, dried, powdered and liquid forms are all poisonous to dogs.
Why don't signs show straight away?
Symptoms can start within 24 hours but more often take a few days to appear; signs of anaemia typically develop several days after eating.
Related foods
All foods: What can dogs eat?Sources
- Garlic and Onion (Allium spp) Toxicosis in Animals — Merck Veterinary Manual
- Onion and garlic poisoning in dogs — PDSA (Published: September 2022)
- Onion, Garlic, Chive, and Leek Toxicity in Dogs — VCA Animal Hospitals
- Poisonous foods for dogs — Blue Cross
- People Foods to Avoid Feeding Your Pets — ASPCA Animal Poison Control
- Which Human Foods Can Dogs Eat and Which Are Dangerous? — American Kennel Club (Updated Oct 21, 2026)
General information from the sources below, not reviewed by a vet and not a substitute for veterinary advice. When in doubt, call your vet.
How kids practise this in PetPrep
In PetPrep a child looks after a realistic dog: meals at the right times, water, walks and care. Knowing what is safe to share is part of being ready for a real pet.