How Poisonous are Onions??

[Stella]

I came home from work today to find that Hartley had managed to get hold of, and eat, the end of a loaf of bread that had mistakenly been left on the counter. It was scallion and potato bread. We think he ate about the last inch of the loaf. He seems to be fine right now. But, I know that onions are bad for dogs. But, bad as in I should take hime to the vet right now, or bad as in he's going to have diarrhoea later??

[Karen, Jasper and Jackdoodle]

Call the vet. It usually takes more than one 'dose" to cause a problem, but not always:

A small amount may not cause a problem since onion toxicity is dose dependent. However, onions in any form (raw, cooked, dehydrated or powdered in a seasoning) can create a life-threatening form of hemolytic anemia in dogs.
What Happens in Onion Toxicity?
Red blood cells carry a protein, hemoglobin, which delivers oxygen to the tissues and organs. Onions contain a substance called thiosulphate which dogs (and cats) lack the enzyme to properly digest. Thiosulphate causes oxidation of hemoglobin in canine red blood cells, which then forms clumps, weakening the cell membranes. These clumps, called Heinz bodies, protrude from the cell and eventually cause rupture, shortening the life span of the cell. When enough red cells are destroyed, anemia occurs and the body is starved for oxygen. Garlic also contains thiosulphate but in smaller amounts.

A significant decrease in red blood cells can cause many problems including heart failure. The number of cells destroyed usually depends on the amount of onion eaten. However, some dogs can develop severe reactions even after eating very little onion. Small amounts of onion fed over a period of time can create illness just as a one-time dose can, due to the gradual build-up of Heinz bodies. On the other hand, some minor cases of onion toxicity may go undetected due to damage of fewer red blood cells. Symptoms sometimes take several days to manifest.

Read more: http://dogs.suite101.com/article.cfm/onion_toxicity_in_dogs#ixzz0NL...

[Debbie and Thomas]

Wow, Karen this info is frightening. I knew about onions being dangerous but had no idea that they could cause such a biological reaction to the red blood cells. I use 1 whole Vidalia onion when I make tomatoe sauce and once in a while I will give Thomas a piece of the pasta left over that has been in this sauce. Never again though-as usual you have enlightened me. Thks

[F, Calla & Luca]

I would wait to see if my dog had any symptoms since the amount of scallions actually ingested is probably small. I do tend to be more laid back about calling or going to the vet though. I don't think the vet would advise anything other than observation but I treat people not dogs.

[Karen, Jasper and Jackdoodle]

Then again, a phone call costs nothing, and peace of mind is invaluable.

[HANNAH 8/2/07 & HONEY 7/2/08]

Hope Hartley is doing ok, please let us know how he is...sorry to hear he got ahold of any onions.

[Sandy]

Oh my - it never stops, does it? Hope Hartley is feeling all right.

[Stella]

He seems to be ok so far. I have been watching him really carefully, and will be over the next few days. He is eating and pooping (so far anyway!!) as normal and exercised fine last night and today. His stomach feels ok, and I keep checking his gums to see if they are pink. He is a big guy (80 pounds) so I am hoping that he is big enough for it not to have an effect on him. We will keep a close eye on him, the first sign of trouble it will be off to the vet - I know we would be able to get in quickly if we have to. These boys are such a constant worry - Sandy you are right - there is always something!!

[Jaime]

I'm glad to finally know why onions are bad for a dog. Thanks for the info.