A dog that keeps biting its hind legs and grunting may have skin diseases or parasites, causing the dog's skin to be itchy and unbearable. This situation will occur. It is best to check whether there are mites and fleas on the dog's body first. Or ticks. If there are parasites, they need to be dewormed in time. If there are no parasites, you can use antifungal ointment or spray on the dog. At the same time, the dog should wear an Elizabethan collar to prevent the dog from licking the medicine. .