"Magoo was a big, playful Labrador retriever who often got himself into sticky situations..."

So begins a story in the latest report from the ASPCA on foods that may be toxic to dogs. It turns out that Magoo got into the pantry and snagged himself about a pound of raisins. He ate the whole thing, of course.

The ASPCA never mentions Magoo's fate. But they do tell us that as little as a handful of raisins can impair a dogs health and has been fatal for some. Ditto for the grape.

Who Knew?

Growing up, I regarded our family dogs as "the first cycle of the dishwasher". They were good about waiting their turn for whatever we left on our plates, and we weren't too concerned about offering them "people food". It never crossed our minds that our dogs health could be affected by a few measly table scraps. What was safe for us, we figured, was safe for our pets.

What's more, whenever I ate grapes, I liked to give one or two to our German Shepherd "Tiffany". The grapes always popped out of her mouth when she tried to bite into them and Tiffany, ever the good sport, refused to give up until she'd squashed each one into submission. It guaranteed at least 60 seconds of harmless fun.

Tiffany was also fond of chewing gum (she chewed it -- wrapper and all -- but didn't swallow it!) We had the sugarless kind, which is often sweetened these days with xylitol.

Little did I know that I might have been poisoning our family pet! (More on xylitol below).

Why are grapes harmful?

As far as grapes and raisins go, no one is sure why they're harmful. It's been confirmed that even grapes grown without fertilizers or pesticides can be toxic to dogs. But not to every dog, and not every time. It's also not known whether small amounts eaten over a long time period could have a cumulative effect.

What we do know is that the end result in nearly all reported cases of grape or raisin toxicity is acute kidney failure. (The term "acute" means that the condition is severe and comes on quickly.) The dog ultimately can't produce urine, which means they can't filter toxins out of their systems -- a process essential to life.

During the twelve-month period in which the effects of grapes were studied, the ASPCA Animal Poison Control Center handled 140 cases involving one or more dogs. Over a third of the dogs developed symptoms ranging from vomiting to kidney failure, and seven dogs died. The ASPCA based their study on reported cases, so naturally there may be cases where a dogs health is entirely unaffected by eating grapes. But until they know all the facts, the Society advises against feeding pets grapes or raisins in any amount.