I won't say it's toxic?! Could be if it's in large quantity. Chilli (A Shih Tzu) used to have a few grapes everyday. But then we learned that it is the reason that gave her crystals in her urinary track. So if possible, don't give them any grapes or raisins. I don't give Gigi any grapes nor raisins... I only give her tiny bits of apples and orange on occasions.