Answers (2)
Grape and raisin (dried grapes) toxicity is well documented in dogs. Although the exact substance that causes the toxic reaction is not yet known, dogs should not eat grapes and raisins because even small amounts can prove to be fatally toxic for a dog.
www.petmd.com/dog/emergency/digestive/e_dg_grape_raisin_toxicity
www.google.com/search?q=dogs+grapes