Scallions, like all vegetables in the allium genus (also known as the onion genus), are toxic to dogs, cats and horses. … Although these may seem totally harmless to you, large amounts of them can wreak havoc on your dog’s red blood cells. Absolutely not worth it.
People also ask, what happens if dogs eat green onions?
Onions contain a toxic principle known as N-propyl disulfide. This compound causes a breakdown of red blood cells, leading to anemia in dogs. The toxin causes oxidative damage to your dog’s red blood cells by attaching to the oxygen molecules in your dog’s red blood cells.
Beside above, how long after eating onion will a dog get sick?

Ame Vanorio
Ame Vanorio is a former science and special education teacher who has morphed into a freelance writer, specializing in blogs about animals, education and environmental science topics. She is the executive director of Fox Run Environmental Education Center and is a licensed wildlife rehabilitation expert. Ame lives on her farm in rural Kentucky with 4 wonderful dogs and lots of other critters!