Is it a myth? No!

I checked on the intranet a few places to be sure the "grapes and raisins are bad for dogs" statement was true. It is very true. One of the sites (snopes.com) known for dissecting intranet myths did research. Even a few raisins or grapes can be deadly to your dog, depending on his weight. Renal failure (failure of the kidneys) can result. Visit http://www.snopes.com/critters/crusader/raisins.asp to see the claim.

I also checked Break the Chain that aims to dispel myths as well (http://breakthechain.org/). They say the same thing. This is not a myth. I also learned, besides chocolate, that onions and macademia nuts can be toxic to dogs.