Mine got into some extra dark chocolate chips a couple of weeks ago. With those, there are actually charts online on ounces consumed per body weight and symptoms to watch for before it's cause to alarm and a trip to the vet.
Good read Dotbat. So weird. In the 80s I remember feeding my GSD and lab a bunch of grapes because it was so funny what they did with them. Had no idea about toxicity, would never have guessed it and nothing happened and it was a lot of grapes.
I've always had big dogs and up until 8 years ago when I found out it was bad for them we've always fed them grapes. We don't anymore because it is supposed to be bad, but I never had one dog get sick from it. Just sayin.
Shepherdmom, my mother did that too for many years too with her cockapoo because she didn't know it was dangerous--that dog lived to 18! The problem from what I understand is that we can't know whether we have a dog that will have the toxic sensitivity, until the dog is in big trouble. When the reaction happens, the dog may already be at death's door going into kidney failure. It's a very mysterious thing as to why some dogs react and others seem not to.
Some dogs go into kidney failure pretty quickly -- and no one understands why. That's why the standard of care seems to be to treat all grape ingestion as a poisoning now.
This is Toxicology Brief from ASPCA-Poison Control is very helpful --http://www.aspcapro.org/sites/pro/files/q.pdf