🥦 Vegetables
Can pets eat Onion?
Contains thiosulfates — toxic to dogs and cats.
- For dogs
- Toxic
- For cats
- Toxic
- Category
- Vegetables
Cross-species safety score
A composite of Onion's dog-side and cat-side safety verdicts, each benchmarked against the other foods rated for that species, so one number shows how Onion compares across both species, not just one. How this score is computed.
Editorial guidance, not a veterinary diagnosis. Only 16 of 160 dog ratings and 16 of 160 cat ratings name an FDA or ASPCA source; every other rating is PlainPetFood's own editorial judgement. Ask your veterinarian before changing what your pet eats.
Onion vs. every tracked food
Dog-side hazard band across PlainPetFood's full food-safety corpus
4 Higher than most in the bottom 1% of 160 foods
Foods, banded by dog-side hazard level
Each bar is a band; taller bars hold more foods. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source PlainPetFood food-safety corpus · 2026-08-09
Onion is toxic, never feed it for both dogs and cats.
Category standing
Toxic on both the dog and cat charts
Dogs and cats share a toxic rating for Onion. Inside vegetables, 4 of 25 dog ratings are toxic - this is a household-wide keep-away, not a species-specific quirk.
Call the ASPCA Animal Poison Control Center at 888-426-4435 (24/7, consultation fee may apply) or your nearest emergency vet immediately, before reading the rest of this page. Have the amount eaten and your pet's weight ready.
Key facts about Onion
Onion is rated toxic in PlainPetFood's food-safety archive. Vegetables lists 13 foods in our archive; 16% of dog-side ratings in that group are unsafe or toxic. Open the species cards below for portions, preparation, and symptom lists tied to this food.
Dog warning signs on record: lethargy, pale gums, vomiting, weakness, reddish urine. Cat warning signs: lethargy, anemia, vomiting, difficulty breathing.
For Dogs
TOXICOne of the most common pet poisonings; onion powder especially concentrated
Full dog guide →For Cats
TOXICCats are more sensitive than dogs; tiny amounts can be fatal
Full cat guide →Onion for dogs vs cats, at a glance
| 🐕 Dogs | 🐈 Cats | |
|---|---|---|
| Safety level | TOXIC | TOXIC |
| Portion | None | None |
| Preparation | - | - |
| Key risk to watch | Thiosulfates cause Heinz body anemia | Thiosulfates extremely toxic to cats |
Per-species safety ratings for onion from PlainPetFood's veterinary-toxicology data. Open the species guides below for full warning signs and emergency steps.
🐕 Onion for dogs
- ⚠Thiosulfates cause Heinz body anemia
- ⚠All forms toxic: raw, cooked, powdered
- ⚠Even small amounts dangerous
🐈 Onion for cats
- ⚠Thiosulfates extremely toxic to cats
- ⚠Even more sensitive than dogs
- ⚠All forms: raw, cooked, powdered
Frequently asked questions
Can dogs eat onion?
Onion is rated toxic for dogs. Key risk: thiosulfates cause heinz body anemia. Do not feed it, if your pet has eaten any, call the ASPCA Animal Poison Control Center at 888-426-4435 (24/7).
Can cats eat onion?
Onion is rated toxic for cats. Key risk: thiosulfates extremely toxic to cats. Do not feed it, if your pet has eaten any, call the ASPCA Animal Poison Control Center at 888-426-4435 (24/7).
More vegetables safety records
Browse other foods in the same category, each with its own dog and cat safety rating.
See the full vegetables safety list for dogs and cats.
Other foods with the same dog and cat safety profile
These foods match onion's recorded dog and cat safety levels, but come from different food categories.
Read our methodology - how this data is sourced, computed, and verified.
Source: ASPCA Animal Poison Control Center + FDA + AAFCO Pet food safety classification (toxicity + FDA enforcement) · August 2026 Safety data combines ASPCA toxicity classifications, FDA pet food enforcement reports, and AAFCO ingredient compliance status.
PlainPetFood publishes an editorial food-safety compilation. When the FDA or ASPCA Animal Poison Control Center names a food as dangerous, that food's page links the source; other ratings are identified as editorial guidance. Its dog and cat ratings, portions, preparation notes and warning signs are rendered from the food-safety archive; a named FDA or ASPCA source is linked above when that authority names this food. See our editorial standards & corrections policy, report a correction, the methodology behind these numbers, or contact the editorial team. Data current as of August 29, 2026.