Is Onion toxic to dogs?

Yes. According to Plants4Pets, Onion is toxic to dogs. Vomiting, breakdown of red blood cells (hemolytic anemia, Heinz body anemia), blood in urine, weakness, high heart rate, panting Toxic principles: N-propyl disulfide This entry has not been manually verified yet — treat it as guidance only.

Is Onion toxic to horses?

Yes. According to Plants4Pets, Onion is toxic to horses. Vomiting, breakdown of red blood cells (hemolytic anemia, Heinz body anemia), blood in urine, weakness, high heart rate, panting Toxic principles: N-propyl disulfide This entry has not been manually verified yet — treat it as guidance only.

Which pets are most at risk from Onion?

Our database flags Onion as toxic to: cats, dogs, horses.

What should I do if my pet eats Onion?

Remove remaining plant material, do not induce vomiting unless a vet instructs you to, and seek professional help immediately with the plant name ready.

Is Onion toxic to cats, dogs? (Allium cepa)

Onion (Allium cepa) is marked as potentially toxic to cats, dogs, horses in the Plants4Pets database. Keep this plant out of reach of curious pets and read the species-specific notes below.

Photos of Onion (Allium cepa)

Onion (Allium cepa) — plant photo, pet toxicity guide

Is Onion toxic to cats, dogs or horses?

Cat Toxic Not verified

Vomiting, breakdown of red blood cells (hemolytic anemia, Heinz body anemia), blood in urine, weakness, high heart rate, panting Toxic principles: N-propyl disulfide
Dog Toxic Not verified

Vomiting, breakdown of red blood cells (hemolytic anemia, Heinz body anemia), blood in urine, weakness, high heart rate, panting Toxic principles: N-propyl disulfide
Horse Toxic Not verified

Vomiting, breakdown of red blood cells (hemolytic anemia, Heinz body anemia), blood in urine, weakness, high heart rate, panting Toxic principles: N-propyl disulfide

Community confirmations show that other users find this rating helpful. They are not verified by our team.

Onion plant details and common names

Family: Liliaceae

Safety advice if a pet eats Onion

Many popular houseplants and garden species can cause vomiting, drooling, skin irritation or more serious symptoms when chewed by cats, dogs or horses. The information on this page is for educational purposes and does not replace a veterinary consultation.

If your pet has eaten any part of Onion (Allium cepa), note the amount ingested, watch for unusual behaviour and contact a veterinarian or pet poison helpline immediately.

Found outdated or incorrect data? Use the report form below or e-mail kontakt@plants4pets.pl with the plant name, species affected and your source — we review every submission.

FAQ: Onion and pet toxicity

Is Onion toxic to cats?: Yes. According to Plants4Pets, Onion is toxic to cats. Vomiting, breakdown of red blood cells (hemolytic anemia, Heinz body anemia), blood in urine, weakness, high heart rate, panting Toxic principles: N-propyl disulfide This entry has not been manually verified yet — treat it as guidance only.
Is Onion toxic to dogs?: Yes. According to Plants4Pets, Onion is toxic to dogs. Vomiting, breakdown of red blood cells (hemolytic anemia, Heinz body anemia), blood in urine, weakness, high heart rate, panting Toxic principles: N-propyl disulfide This entry has not been manually verified yet — treat it as guidance only.
Is Onion toxic to horses?: Yes. According to Plants4Pets, Onion is toxic to horses. Vomiting, breakdown of red blood cells (hemolytic anemia, Heinz body anemia), blood in urine, weakness, high heart rate, panting Toxic principles: N-propyl disulfide This entry has not been manually verified yet — treat it as guidance only.
Which pets are most at risk from Onion?: Our database flags Onion as toxic to: cats, dogs, horses.
What should I do if my pet eats Onion?: Remove remaining plant material, do not induce vomiting unless a vet instructs you to, and seek professional help immediately with the plant name ready.

Report an error or missing data

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Wrong toxicity for a cat, dog or horse
Missing or incorrect plant name
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Additional veterinary or botanical reference

Include the plant name (Allium cepa), affected pet species and, if possible, a link to your source. We usually respond within a few business days.