The act of oral sex itself is a marginal sex act, and the probability of sexually transmitted diseases is not particularly high, but it is possible. If the active oral sex party oral ulcers or small wounds inside the mouth, in the marginal sex act may constitute an exchange of body fluids with the passive party. Once the exchange of body fluids is constituted, the pathogenic pathogens in the body of the passive party will be transmitted through body fluids to the active party of oral sex, resulting in the transmission of sexually transmitted diseases. One of the most important diseases is the human papillomavirus infection resulting in condyloma acuminata, and human immunodeficiency virus infection after the formation of AIDS, syphilis, etc. are possible, they will be transmitted through this behavior. Therefore, it is important to protect yourself and not to take any chances.