Fruits to avoid feeding your dog include grapes and raisins, peaches, plums and persimmons.
The specific problem with persimmons, peaches, and plums are the seeds or pits. The seeds from persimmons can cause inflammation of the small intestine in dogs. They can also cause intestinal obstruction, a good possibility if a dog eats the pit from a peach or plum. Plus, peach and plum pits contain cyanide, which is poisonous to both humans and dogs should the pit be broken open and consumed.
According to Pet Poison Helpline, grapes and raisins have been known to cause acute renal (kidney) failure in dogs. With kidney failure, a pet’s ability to produce urine decreases, which means they are unable to filter toxins out of their system.
Unfortunately, the reason for kidney failure and the amount of grapes/raisins necessary to be toxic to pets is unknown, so all cases of ingestion have the potential to be grave. Depending on the size of the dog, as little as four grapes/raisins can have an adverse effect on your fuzzy friend.