A dog suddenly hides when he is sick. It may be because he is afraid, wants to protect himself, or knows that he is about to die. Therefore, it is best to send the dog to the hospital for examination in time to ensure that it is not life-threatening. Treat it actively and do not scare the dog. . Some dogs may hide because they are afraid of going to the hospital. At this time, it is best for the owner to patiently comfort the dog and not to overly frighten the dog. The owner can give the dog snacks or toys to distract it.