Interestingly enough, too much celery can cause dogs to urinate a great deal more than usual. But cut into small, chewable, digestible pieces — with the leaves removed — celery is okay for dogs in limited amounts. read more
They can eat raw or cooked celery. Raw celery is hard, but able to chew easily by a dog if in a bite sized piece. Unlike a potato, raw celery should not be as risky if eaten as-is. read more