Can dogs eat onions?
UNSAFE Category: Vegetable · Source verified September 2026
Onions, in every form — raw, cooked, powdered or dehydrated — damage dog red blood cells through N-propyl disulfide, causing hemolytic anemia. Cats and Japanese breeds like Shiba Inu and Akita are especially sensitive, but all dogs are at risk. Onion powder in baby food, soups and seasonings makes accidental poisoning common.
How much is dangerous?
- Clinical signs are documented in dogs at 15–30 g of onion per kg of body weight — about 1.5–3% of body weight, roughly 300–600 g (a few large onions) for a 44 lb dog.
- Every form counts, raw or cooked, and onion powder is far more concentrated by weight than fresh onion, so seasoned leftovers and soups matter.
- Cats are even more sensitive (documented around 5 g/kg), so keep onion-family foods away from cats too.
Dose data: Merck Veterinary Manual: Garlic and Onion Toxicosis.
Symptoms to watch for
- lethargy
- pale gums
- red or brown urine
- weakness
- rapid breathing
Because the damage is to red blood cells, signs are delayed — hemolysis typically shows 3–5 days after ingestion.
If you suspect poisoning: call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435 (available 24/7). Do not induce vomiting unless instructed by a professional.
Quick answers
Can dogs eat onions?
No. Onions, in every form — raw, cooked, powdered or dehydrated — damage dog red blood cells through N-propyl disulfide, causing hemolytic anemia. Cats and Japanese breeds like Shiba Inu and Akita are especially sensitive, but all dogs are at risk. Onion powder in baby food, soups and seasonings makes accidental poisoning common.
How much onions is toxic to a dog?
Clinical signs in dogs are documented from 15–30 g of onion per kg of body weight (about 1.5–3% of body weight) — a few large onions for a 44 lb dog. All forms count, including cooked onion and the far more concentrated powder.
What are the symptoms if my dog eats onions?
Watch for lethargy, pale gums, red or brown urine, weakness, rapid breathing. Because the damage is to red blood cells, signs are delayed — hemolysis typically shows 3–5 days after ingestion. When in doubt, call your vet.
What should I do if my dog ate onions?
Call your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435 right away. Do not wait for symptoms — early treatment is dramatically cheaper and safer.
Related foods
Can dogs eat garlic? · Can dogs eat wild mushrooms? · Can dogs eat tomatoes? · Can dogs eat potatoes? · Can dogs eat pickles? · Can dogs eat carrots?
Source: ASPCA Animal Poison Control. This page is informational and is not veterinary advice.