Can dogs eat Onion?

Avoid
Onion can damage red blood cells in dogs and may cause anemia.

Quick notes

Sources

All pets (comparison)

Pet Safety Notes
Dog Avoid Onion can damage red blood cells in dogs and may cause anemia.
Cat Avoid Cats are especially sensitive to onion toxicity.
Rabbit Avoid Onion should not be fed to rabbits.
Parrot Avoid Onion may irritate the digestive system and should be avoided.