Peaches pits are poisonous if swallowed by humans, and they can be fatal if eaten by dogs. They contain cyanide which can lead to severe health complications. The symptoms of this disease include a drooping head, vomiting, convulsions, breathing difficulties, irregular heartbeat, excessive salivation, and dilation of the pupils. So, if your dog has eaten a peach pit, instantly contact your veterinarian for instructions or head to the nearest veterinarian hospital.