Emergency contraceptives commonly used are levonorgestrel and mifepristone. There are two sizes of levonorgestrel, one is 1.5mg and the other is 0.75mg. If it is 1.5mg, you can take 1 tablet within 72 hours of sex. If it is 0.75mg, it is within 72 hours after sexual intercourse, 2 tablets need to be taken, and 12 hours interval is needed in between. If it is mifepristone, it is fine to take 25mg, i.e. 1 tablet, and it is best to apply it within 72 hours after sex, and the effect is still possible. But the success rate of emergency contraceptive pill contraception can only reach 85%-90%, so there are more than 10% of people are unsuccessful in contraception, if necessary, timely examination.