Dogs cannot eat raisins as they are toxic to them. Raisins, along with grapes, can cause severe kidney damage that may lead to acute kidney failure, which can be fatal for dogs. Even a small amount, sometimes as little as one raisin, can be dangerous because the exact toxic substance is unknown and the reaction varies from dog to dog. Symptoms of raisin poisoning include vomiting, diarrhea, loss of appetite, lethargy, and signs of kidney failure such as decreased or absent urination. Immediate veterinary care is essential if a dog consumes raisins to prevent serious health consequences or death.