The harmless-looking grapes are one of the human foods that must not be given to dogs. People commonly love to share whatever they are eating with the pet but because of the supposed harmful effects, pet owners would not dare give the pet a single grape. Studies conducted on grape toxicity have verified that it was not caused by fertilizers or pesticides. One thing is for sure though - grapes can cause renal failure in canines. Grape toxicity would cause the dog severe pain and similar to other cases of poisoning, it can result in the death of the dog.