Growli
Let's go

Pet safety

Is White Onion toxic to cats?

Allium cepa 'Sturon'

Toxic to cats

Yes — white onion is toxic to cats according to the ASPCA. Keep it well away from any cat that chews plants; reactions can be significant. This classification follows the ASPCA Toxic and Non-Toxic Plant List. ASPCA lists Allium species, including the onion (Allium cepa), as toxic to dogs and cats. The organosulfoxides they contain cause oxidative damage to red blood cells and Heinz-body haemolytic anaemia, with cats the most susceptible. Signs include vomiting, weakness, pale gums, lethargy and reddish-brown urine; all forms, raw, cooked or dried, are dangerous.

What to do if your cat ate white onion

  1. Remove any plant material from your cat's mouth and move white onion 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 white onion to the appointment so it can be treated correctly.

General guidance, not veterinary advice. If you think your cat has eaten white onion, contact your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 — do not wait for symptoms to worsen.

Is white onion toxic to cats? — FAQ

Is white onion toxic to cats?

Yes — white onion is toxic to cats according to the ASPCA. Keep it well away from any cat that chews plants; reactions can be significant. ASPCA lists Allium species, including the onion (Allium cepa), as toxic to dogs and cats. The organosulfoxides they contain cause oxidative damage to red blood cells and Heinz-body haemolytic anaemia, with cats the most susceptible. Signs include vomiting, weakness, pale gums, lethargy and reddish-brown urine; all forms, raw, cooked or dried, are dangerous.

What are the symptoms if a cat eats white onion?

ASPCA lists Allium species, including the onion (Allium cepa), as toxic to dogs and cats. The organosulfoxides they contain cause oxidative damage to red blood cells and Heinz-body haemolytic anaemia, with cats the most susceptible. Signs include vomiting, weakness, pale gums, lethargy and reddish-brown urine; all forms, raw, cooked or dried, are dangerous. Signs usually appear soon after chewing rather than hours later — watch for drooling, pawing at the mouth, vomiting, loss of appetite, or unusual lethargy after your cat has had access to white onion.

What should I do if my cat ate white onion?

Stay calm. Remove any plant from your cat's mouth and take the plant away. Note how much was eaten and when, and do not induce vomiting unless told to. Call your vet or the ASPCA Animal Poison Control Center on (888) 426-4435 and follow their advice; a leaf or photo helps the vet treat it correctly.

Is white onion toxic to dogs too?

The ASPCA classification Growli uses applies to both cats and dogs: White Onion is toxic to dogs as well. See the full white onion pet-safety guide for both species.

What is a cat-safe alternative to white onion?

For a similar look without the risk, see the best cats-safe plants list — every plant there is ASPCA non-toxic to cats and dogs.

Full white onion pet-safety