6. Grapes and RaisinsBoth cats and dogs are extremely at risk with grapes and raisins. Although it is unclear exactly what in them is poisonous, they can cause sudden kidney failure. The signs of possible poisoning from grapes and raisins are similar to other signs of poison and include tiredness, vomiting and diarrhea. If you suspect or know your cat has eaten a grape bring them to the animal hospital immediately. Make sure your children are also aware of the human foods that are toxic to pets as these foods are common for children to eat.