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Pet safety

Is Onionstoxic to cats & dogs?

Allium cepa

Toxic to pets

Is onions safe for cats and dogs?

No — onions is toxic to cats and dogs and should be kept well away from pets that chew plants. This classification follows the ASPCA Toxic and Non-Toxic Plant List, the most widely used reference for companion-animal plant safety in the US and the standard most UK vets cite as well. ASPCA lists Allium cepa as toxic to cats, dogs, and especially horses due to N-propyl disulfide, which causes haemolytic anaemia. Both raw and cooked onion are toxic. Garlic, leeks, and chives carry the same risk.

What happens if a pet eats onions?

ASPCA lists Allium cepa as toxic to cats, dogs, and especially horses due to N-propyl disulfide, which causes haemolytic anaemia. Both raw and cooked onion are toxic. Garlic, leeks, and chives carry the same risk. Signs usually appear soon after chewing rather than hours later. If you see drooling, pawing at the mouth, head-shaking, vomiting, loss of appetite, or unusual lethargy after your pet has had access to onions, treat it as a suspected ingestion and act on the steps below.

What to do if your pet ate onions

  1. Remove any plant material from your pet's mouth and move onions out of reach.
  2. Note how much was eaten and when, and watch for drooling, vomiting, or lethargy.
  3. Do not induce vomiting unless a vet or poison-control specialist instructs you to.
  4. Call your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 and follow their advice.
  5. Bring a leaf or photo of onions to the appointment so it can be treated correctly.

This page is general guidance, not veterinary advice. Pets vary, and a reaction may be to soil, fertiliser, or pesticide rather than the plant. If you are worried, always contact a vet or the ASPCA Animal Poison Control Center on (888) 426-4435 — do not wait for symptoms to worsen.

Pet-safe alternatives to onions

Want the same look without the risk? These plants are listed as non-toxic to cats and dogs by the ASPCA and have similar care needs:

Onions and pets — frequently asked questions

Is onions toxic to cats?

Onions (Allium cepa) is toxic to pets to cats according to the ASPCA. ASPCA lists Allium cepa as toxic to cats, dogs, and especially horses due to N-propyl disulfide, which causes haemolytic anaemia. Both raw and cooked onion are toxic. Garlic, leeks, and chives carry the same risk. Keep it out of reach and contact your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 if your cat chews it.

Is onions toxic to dogs?

The ASPCA lists the same toxicity status for dogs as for cats: Onions is toxic to pets. Dogs often chew more enthusiastically than cats, so a toxic plant like onions is best removed from the floor and low shelves entirely.

What happens if my pet eats onions?

ASPCA lists Allium cepa as toxic to cats, dogs, and especially horses due to N-propyl disulfide, which causes haemolytic anaemia. Both raw and cooked onion are toxic. Garlic, leeks, and chives carry the same risk. Signs usually appear soon after chewing rather than hours later. If you see drooling, pawing at the mouth, head-shaking, vomiting, loss of appetite, or unusual lethargy after your pet has had access to onions, treat it as a suspected ingestion and act on the steps below.

What should I do if my cat or dog ate onions?

Stay calm. Remove any remaining plant material from your pet's mouth and take the plant away so they cannot eat more. Note roughly how much was eaten and when. Do not make your pet vomit unless a vet or poison-control specialist tells you to. Call your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 (a consultation fee may apply) and follow their advice. Bringing a photo or a leaf of onions to the appointment helps the vet treat it correctly.

What are pet-safe alternatives to onions?

If you want a similar look without the risk, good non-toxic swaps include cucumber, lettuce, bean, pea. All of these are listed as non-toxic to cats and dogs by the ASPCA, so they suit a home where pets have access to your plants.

Full onions care

Pet-safety is one piece of the picture. For light, watering, soil, and troubleshooting, see the complete onions care guide, or browse the full pet-safe plant library to check another plant before you buy it.