AIDS generally can not be transmitted through saliva, there are other special circumstances may be infectious. 1. Can not be infectious: although the saliva of AIDS patients can be separated from the virus, but the content is extremely small, so the amount of virus in the unit is not enough to cause infectiousness, the general situation through, saliva will not spread. 2. May be contagious: If two people have bleeding gums, mouth ulcers, etc., it is possible that through kissing saliva contact, direct contact with the trauma, so it may be contagious. AIDS patients and infected people are the source of infection, HIV is mainly present in the blood, semen, vaginal secretions, ascites, cerebral effusion and breast milk of infected people and patients, the clinical mainly through sexual contact transmission, transmission through blood, mother-to-child transmission. If there is a high-risk contact, it is recommended to go to the hospital in time for examination and clear diagnosis, so as not to delay the condition.