The sooner you take levonorgestrel tablets after intercourse, the better, and the sooner you take them, the faster they work. This drug is a kind of progestin drug, its mechanism of action is to inhibit female ovulation, interfere with the fertilized egg in the uterus to bed. If the patient has already ovulated, the effect will not be very good after taking it, so it is best to take it before the woman ovulates, so that the contraceptive effect is more efficient. If ovulation has already occurred, it interferes with the uterine lining, causing it to be out of sync with the development of the fertilized egg, which can also serve as a contraceptive. However, the contraceptive effect of this drug is not 100%, and it can also be found that taking this drug causes pregnancy, so such a drug should be taken as little as possible.