Can dogs eat onions or garlic?
Onions, garlic, leeks and chives (the Allium family) contain sulfur compounds that damage red blood cells and can cause anemia. Raw, cooked, dried and powdered forms are all a risk, and signs can take days to appear.
Call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435 (a fee may apply). Tell them your dog’s weight, what form it was (raw, cooked, powder) and roughly how much. Your dog may look completely normal at first — that doesn’t mean it’s safe.
Why are onions and garlic dangerous?
Onions, garlic, leeks and chives all belong to the Allium family. When they’re chopped, cooked or chewed, they release sulfur-containing compounds that damage red blood cells. The damaged cells break down, which can lead to hemolytic anemia — not enough healthy red blood cells to carry oxygen.
According to the Merck Veterinary Manual, garlic is 3–5 times more toxic than onion, and cats are even more sensitive than dogs.
Which forms are risky?
- Raw and cooked onions, garlic, leeks, shallots and chives
- Powders, flakes and dried soup mixes — these are concentrated, so small amounts matter more
- Foods that contain them: gravy, stock, soups, pizza, garlic bread, many sauces, seasoned meat and some baby foods
How much is a problem?
The Merck manual reports clinical signs in dogs after eating about 15–30 g of raw onion per kg of body weight. For a 10 kg (22 lb) dog, that’s about 150–300 g — one medium onion or less. Concentrated powders and garlic take far less, and repeated small amounts over several days can add up. That’s why vets recommend avoiding Allium foods completely.
Signs to watch for
Damage to red blood cells starts within a day, but signs of anemia usually take a few days to show. Watch for:
- Vomiting, diarrhea or loss of appetite early on
- Weakness, tiredness or not wanting to exercise
- Pale or yellowish gums
- Fast breathing or a racing heart
- Red or dark brown urine
- Collapse — an emergency
How to keep your dog safe
- Don’t share table scraps that were cooked with onion or garlic, including gravy and stock.
- Check ingredient lists on baby food and broth before using them for your dog.
- Keep onion bags and garlic off the floor and low shelves.
Frequently asked questions
Isn’t a little garlic good for dogs?
You’ll see claims online that garlic repels fleas or boosts health, but those benefits aren’t proven and garlic is more toxic than onion. Veterinary sources advise against feeding it.
My dog ate a small piece of cooked onion. Is that an emergency?
A single small piece is unlikely to cause problems in a medium or large dog, but the risk depends on your dog’s size and how much it ate, and powders are much stronger. Call your vet or a poison control line to check.
Are onions toxic to cats too?
Yes — cats are even more sensitive than dogs. Keep all Allium foods away from cats as well.
Sources
This article is general information, not veterinary advice. Every pet is different — for questions about your own pet’s health, talk to your veterinarian.