As long as they do not grow beyond 7mm in diameter, your dog will be fine. The Water beads like Orbeez are not toxic for your dog. But if he swallows and the Orbeez grows more than 7mm in diameter, it will be a problem for your dog.  He may have stomach aches or constipation problems. The doctor may recommend endoscopy to remove the Orbeez from your furry friend's stomach.