Sexually transmitted diseases (STDs) are a group of infectious diseases that are transmitted through sexual contact, similar sexual acts and indirect contact, and can not only occur in the genitourinary organs, but also invade the lymph nodes belonging to the genitourinary organs through the lymphatic system, and even invade the important tissues and organs of the whole body through hematogenous dissemination. The broad sense of STD includes many kinds: syphilis, gonorrhea, non-gonococcal urethritis, condyloma acuminatum, genital herpes, AIDS, soft chancre, venereal lymphogranuloma, genital candidiasis, trichomoniasis, bacterial vaginosis, lice, scabies, hepatitis B and ringworm are also included, and there are more than 20 kinds of STD. And we people often say that STDs mainly refers to the first eight. The transmission of STDs includes sexual transmission: is the main mode of transmission of STDs. 1, indirect contact transmission: contact with clothing contaminated by pathogens, etc. Blood and blood products transmission: syphilis and AIDS. Organ transplantation, artificial insemination transmission: such as AIDS. 2, occupational transmission: mainly refers to occupational exposure such as medical and nursing laboratory personnel and police officers. Placental transmission: transmitted from sick mother to fetus, such as syphilis, chlamydia, mycoplasma, HIV infection, etc. 3, obstetric transmission: gonorrheal conjunctivitis, chlamydia, HIV infection, etc. Many friends have sex or other daily life things, they will worry and then fear AIDS. In fact, some behaviors are not really high-risk sexual behavior. So what kind of behavior is high-risk sex? Only true high-risk behaviors or high-risk sexual behaviors have the possibility of HIV infection. In order to eliminate the fear psychology hope that the majority of friends correctly understand this point. High-risk sex is the act of exchanging bodily fluids with others, that is, someone else’s bodily fluids entering their body or their bodily fluids entering someone else’s body, to put it professionally, it is unsafe sexual intercourse without any protection. Specific high-risk behavior or high-risk sexual behavior are as follows: 1, through the sexual route of high-risk sex: really counted as high-risk sexual behavior is not to take any protective measures of sex, such as unprotected intercourse (male and male GJ, male and female XJ), multiple sexual partners, etc.. 2, high-risk behavior through the blood route: sharing syringes with other people to inject drugs intravenously is high-risk behavior (if they use disposable needles there is no possibility of HIV infection). Sharing needles for intravenous drug use; sharing syringes or other devices that can pierce the skin; using untested blood or blood products. 3. High-risk behavior through mother-to-child transmission: HIV-positive women who become pregnant and give birth; HIV-positive mothers who breastfeed may cause HIV infection in their children. 4, other possible ways to cause blood transmission: such as for tattoos, haircuts, pierced ears, beauty, pedicure with the knife is not sterilized lacerations; with other people to share shavers, electric razors, toothbrushes; trauma and fights caused by bleeding; rescue of the wounded, the rescuer’s broken skin contact with the wounded blood, and confirmed that the other party has AIDS infection. In addition, oral sex may transmit AIDS, but the probability is low. It is still safer to use condoms. It is important to know that HIV infection is only possible in the case of high-risk behavior or high-risk sexual behavior. Other than that, other behaviors are unlikely to contract AIDS.