How poisonous are grapes to dogs?

Grapes and raisins can cause serious, and even deadly, kidney damage in dogs. It is unknown what causes the poisoning, but it is likely to be found in the pulp of the fruit; grape seeds do not seem to be poisonous. There are reports that as little as 3 grams of raisins per kg body weight and 20 grams of grapes per kg body weight result in poisoning.

It often takes several hours after the dog eats raisins/grapes until symptoms of poisoning develop. Often it starts with vomiting and diarrhoea and is later followed by kidney failure. If the dog does not show any signs of poisoning and does not have increased kidney values 3 days after it has eaten raisins/grapes it is unlikely to develop any symptoms. If your dog has managed to eat raisins or grapes you should seek veterinary care immediately. If you get your dog to the vet early enough an emetic (medication to induce vomiting) can be used. If not, or if your dog shows symptoms of feeling unwell, it will likely need to be hospitalised for supportive care and monitoring by veterinary staff.