This question was brought up through another post and several people were unaware that grapes and raisins can be toxic to dogs so I thought it important enough to start a thread on. Grapes and raisins can cause acute renal, or kidney failure in dogs. It can only take a few for this to happen. I used to feed grapes to my little dachshund all of the time because she loves them, but have stopped because of them being toxic. I have since counted my lucky stars that nothing ever happened to my sweet little doggy due to me feeding her grapes. My dog was lucky, but there are many other peoples dogs that have not been. Here is an article that went around on the e-mail (probably still is going) and was verified by snopes as true on grapes being toxic. Please read and educate yourself if you haven't heard of this before.
http://www.snopes.com/critters/crusader/raisins.asp
http://www.snopes.com/critters/crusader/raisins.asp