What Happens If a Dog Eats Scallions?

Scallions can cause poisoning because they contain n-propyl disulfide, which destroys red blood cells and causes anemia.

This leads to fast pulse, abnormal bleeding, thirst, blood in urine and pale mucous membranes.

Scallions also irritate the gut, causing stomach pain, diarrhea and vomiting; see a vet if the dog ate a lot.