Say NO to Onions

Onions are toxic to dogs.

The toxicity is dose dependent, so the bigger the animal, the more onion need be consumed to cause a toxicity. Onion toxicity causes a Heinz body anemia. Heinz bodies are small bubble-like projections which protrude from a red blood cell and can be seen when the cells are stained. This "bubble" is a weak spot in the red blood cell and, therefore, the cell has a decreased life-span and ruptures prematurely.

If numerous red cells are affected and rupture, anemia can result. It is a form of hemolytic anemia. Onions are only one of the substances which can cause Heinz body anemia. Other substances such as Acetominophen (Tylenol) and benzocaine-containing topical preparations can also cause Heinz body anemia in the dog.