Whether it is useful to take emergency contraceptive drugs after 3 days of intercourse depends on whether it has been more than 72 hours. If it has been more than 72 hours, it is not very meaningful to take oral emergency contraceptives at this time, so for the sake of health and to reduce adverse reactions, you can choose not to take them first. But be sure to buy early pregnancy test paper after 12 days to test to rule out the chance of conception. If it is less than 72 hours after 3 days of intercourse, you can take oral emergency contraceptive medication, which will have the effect of contraception, and the success rate of contraception is about 80%. When taking the emergency contraceptive pill, you can choose to take it on an empty stomach or 2 hours after a meal to avoid the possibility of reducing the effectiveness of the emergency contraceptive pill. It is also important to buy test strips after taking the emergency contraceptive pill to rule out the chance of conception, as it is not 100% contraceptive.