vegetable
Onions
DANGEROUS
No. Onions and other allium vegetables damage a dog's red blood cells and can cause anaemia.
If your dog has eaten this item, contact your vet or an emergency veterinary service now.
If your dog is showing symptoms such as difficulty breathing, seizures, collapse, severe vomiting, unconsciousness or other serious symptoms, seek emergency veterinary care immediately.
What to do
Contact your vet for advice and mention how much was eaten and when. Watch for weakness or pale gums over the following days.
When to contact a vet: Contact a vet if a meaningful amount was eaten, or at any sign of weakness, pale gums or laboured breathing.
Symptoms to look for
- lethargy
- weakness
- pale gums
- rapid breathing
- vomiting
- reduced appetite
- dark or reddish urine
Why
Onions belong to the allium family, along with garlic, leeks, shallots and chives. They contain compounds that damage red blood cells and can lead to haemolytic anaemia. All forms count, including raw, cooked, dried, powdered and onion in gravies, stocks and cooked leftovers. Signs can take a few days to appear.
- Substances of concern
- N-propyl disulfide, organosulfur compounds
- Parts to avoid
- The whole vegetable, raw or cooked, plus onion powder and onion-containing sauces.
- How much matters
- Larger amounts and repeated small amounts both matter. Concentrated forms such as onion powder are more potent by weight.
- Severity
- Moderate to high
Sources
- ASPCA Animal Poison ControlPrimary authoritative — Toxicity
- PetMDVeterinary information — Toxicity
Information reviewed against recognised veterinary and animal-safety sources. Source organisations are independent of Is It For Dogs unless otherwise stated.
Last reviewed 6 September 2026 · next review due September 2027.
Safety classifications are based on available expert and veterinary information. Individual dogs may react differently, particularly dogs with allergies, existing health conditions or specific dietary requirements.
Important: Is It For Dogs provides general information about the safety of foods, plants, drinks, ingredients and other items around dogs. Our information is based on sources we consider reliable and is intended to help dog owners make informed decisions. It is not a substitute for advice from a qualified veterinary professional. Read more
Dogs can react differently depending on their size, age, health, allergies, medications, the amount consumed and other circumstances. An item classified as Safe is not necessarily suitable for every individual dog.
If your dog has eaten something potentially poisonous or dangerous, has eaten an unknown substance, or is showing concerning symptoms, contact your veterinarian or an emergency veterinary service immediately.
Do not induce vomiting or give your dog medication unless specifically instructed to do so by a veterinary professional.
Also known as onion, onions, spring onion, shallot, leek · Allium cepa