Suspected of being bitten by a dog, through the history of contact with the dog, observation of wounds, physical symptoms to determine. 1. Contact with the dog history: usually whether often play with the dog, whether the family has a dog, there are cases where the possibility of being bitten by the dog a little more, no contact with the dog, there is no dog bite. 2. Observe the wound: observe whether there is a wound, whether the wound has teeth marks, if it is a dog bite wound will be a little rounded. Observe whether there is bleeding in the wound, the dog’s teeth are sharper, the bite may bleed and the wound is deeper. Observe the area of the wound, the area of the wound is larger, the chances of being bitten by the dog is also larger. 3. Physical symptoms: After being bitten by the dog to observe the changes in the body, the incubation period may not have any symptoms, the prodromal period will appear low fever, numbness of the wound, itching, headache, generalized tenderness, nausea, irritability, fear and anxiety, etc., the emergence of the acute neurological period of episodes of pharyngeal muscle spasms, respiratory difficulties, urinary and fecal difficulties, sweating and salivation, fear of water, fear of the wind, etc., through the above symptoms to be suspected of having been bitten by the dog before. The above symptoms should be used to suspect a previous dog bite. At present, rabies virus infection can not be treated, the mortality rate can be up to 100%, so dog bites or scratches should be timely treatment of wounds and rabies vaccination.