The principle of Eusebio contraception is to inhibit ovulation, so that when ovulation does not occur in the patient, pregnancy does not occur. The main component of Eusebio is progestin, with only a small amount of estrogen. It is usually recommended to be taken from the first or fifth day of menstruation, during which time the gonadal axis is suppressed and ovulation does not occur. During the follicular phase, that is, during and just after menstruation, the patient’s progesterone level should be low and the patient’s estrogen and follicle stimulating hormone levels should be high during this time. Ovulation occurs when the patient’s estrogen level reaches 200 pg/mL and is maintained for 48 hours, and the patient’s luteinizing hormone and follicle stimulating hormone reach their peak. However, the progestogen Eusyn, which suppresses the peak of estrogen, can suppress the peak of luteinizing hormone, so the patient will not ovulate and the effect of contraception can be achieved.