It is necessary to take blocking medication for one high-risk behavior, especially for HIV. If there is an infectious disease after high-risk behavior, even if it is once there is still a risk of being infected, if there is a blocking drug can be taken, it is recommended to still take the blocking drug. Clinically, the risk of HIV infection is still relatively high, and can be transmitted vertically through blood contact, sexual contact and mother-to-child transmission. If you have this kind of high-risk behavior, it is recommended that you still need to take HIV blocking drugs as soon as possible. It is best to take the first dose of blocking medication within 24 hours, not more than 72 hours, and subsequent doses should be taken regularly as prescribed by the doctor. Although it is a high-risk behavior, can not take a chance, for safety reasons, it is recommended to consult a doctor in a timely manner, in accordance with the doctor’s instructions to take blocking drugs.