Although peaches themselves are not inherently bad for dogs to eat, the pits of them are toxic. Dog owners should never let their pets eat the pits out of peaches, as they can be extremely harmful.
They are just one of the many different kinds of fruit pits which can be problematic for most dogs and even lethal if they are consumed enough over time. If you currently own any type of dog right now, it is highly recommended that you keep these pits as far away from them as possible.
If your dog consumes a peach pit, you should contact a veterinarian as soon as possible.