We use to have a grape harbor around our patio fence.......my 8 year old Golden Retriever had ate grapes every year ( I noticed her ears always were worse after that so I tried to control her eating them much). At 8 years old she ate a bunch and got sick in the night....we rushed her to the vet the next morning and she died within a few minutes after arriving. I do think her age had something to do with it.....her body just could not tolerate grapes at that age. There may have been other things that caused it that I was not aware of......that's when I read that grapes could be problem. I cut down the grapes as I have two goldens now......never going to take that chance again.