At present, the incidence of HIV is increasing in China, especially among young and middle-aged people and even college students, and it is almost like “talking about HIV”. First of all, you need to clearly grasp an effective emergency blocking time, that is, the golden 72 hours, especially within 2 hours, the effective blocking rate can reach more than 95%. Once this golden time is missed, the chance of infection will be greatly increased. The most common combination of blocking drugs is dolutegravir plus tenofovir plus emtricitabine. This drug can be purchased at the local infectious disease hospital’s HIV clinic or at the disease control center. In order to avoid HIV infection, it is necessary to be clean and avoid having sex with people of the opposite sex other than your spouse, and even if you have sex, you must remember to wear a condom in order to effectively isolate the HIV virus from your body.