Can Dogs Have Onions?

Answer: No — toxic.

No. Dogs must not eat onions in any form — raw, cooked, powdered or in broth. Onions are toxic to dogs and can cause serious, even life-threatening anaemia. If your dog has eaten onion, call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435 right away.

Why onions are toxic to dogs

Onions contain a compound called N-propyl disulfide. In dogs it damages red blood cells: it oxidises haemoglobin, damaged cells form clumps called Heinz bodies, and the cells rupture. The result is haemolytic anaemia — the blood can no longer carry enough oxygen around the body. Cooking does not neutralise the toxin, and onion powder is more concentrated than fresh onion. According to the AKC, 100 g of onion per 20 kg of a dog’s weight can cause toxic effects — a 45-pound dog would only have to eat one medium-to-large onion.

Symptoms of onion poisoning

Symptoms usually take 24 to 72 hours to appear, because the red blood cell damage builds up over time. Watch for:

  • Vomiting, drooling, diarrhoea and loss of appetite
  • Weakness and lethargy
  • Pale or yellow gums
  • Rapid breathing and an elevated heart rate
  • Red or brown urine
  • Fainting or collapse in severe cases

What to do if your dog ate onion

Call your vet or ASPCA Animal Poison Control at (888) 426-4435 immediately — do not wait for symptoms to appear. Note how much your dog ate and when. Do not try to make your dog vomit unless a vet tells you to. Your vet may need to run blood tests to check for anaemia, and serious cases need emergency treatment.

How to keep your dog safe

Never add onion to your dog’s food, and keep onion powder, soup mixes, sauces, baby food and leftovers that contain onion out of reach. Remember that garlic, leeks, chives and shallots are in the same family and are also toxic to dogs.

Frequently asked questions

Are cooked onions safe for dogs?

No. Cooking does not make onions safe. The toxic compound survives heat, so cooked onions, onion powder and broth made with onion are all toxic to dogs.

Is a tiny bit of onion OK for dogs?

No amount of onion is safe for dogs. Even small amounts can be harmful, especially for small dogs, and the risk grows with the amount eaten.

What about garlic, leeks and chives?

Garlic, leeks, chives and shallots belong to the same allium family as onions and are also toxic to dogs. Keep all of them away from your dog.

How long after eating onion do symptoms appear?

Symptoms usually appear 24 to 72 hours after eating onion, as damaged red blood cells break down. Early signs are vomiting and lethargy; later signs include pale gums, weakness, rapid breathing and dark urine.

What should I do if my dog ate onion?

Call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435 immediately. Do not wait for symptoms, and do not try to make your dog vomit unless a vet tells you to.

Sources

ASPCA — People Foods to Avoid Feeding Your Pets. American Kennel Club — Which Human Foods Can Dogs Eat and Which Are Dangerous?.

This page was reviewed for accuracy against AKC and ASPCA guidance. It is general information only and is not a substitute for veterinary advice. If your dog has eaten onion, call your vet or ASPCA Poison Control at (888) 426-4435 immediately.

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