Eating a lot of them will cause this, so just eat in moderation. Just a few
Why Does Eating Cherries Or Grapes Cause Diarrhea?
The best answer would probably be that dogs are carnivores and if you fed turkey to a horse they would get diarrhea. I don't know if cherries are a problem for dogs in the toxic sense but in more recent years it has been found that grapes are very toxic to dogs; this includes raisins. DO NOT feed grapes to your dog any more! Also, spread the word because not many people seem to know this fact. Off the top of my head I can't remember what they effect but if you google it I'm sure you'll find the information.