HIV blocking medication is not free to receive, but needs to be purchased by the patient. Only for patients diagnosed with HIV, their treatment medication is free, and the state will provide basic antiviral medication for HIV antiviral treatment. The HIV blocking medication needs to be purchased and taken as soon as possible within 2 hours after the high-risk behavior occurs so that the blocking effect can be maximized. If the medication is not available within 2 hours, it should be purchased and taken as soon as possible within 48 hours. If for any reason you cannot get the medication within 48 hours, you should try to take the medication within 72 hours, so that you can take a complete blocking cycle and still have a chance of success. Of course, if you want to avoid HIV infection, you should avoid high-risk behavior to better protect yourself.