The most significant effect on the body of taking emergency contraceptive pills twice in two days may be a greater effect on menstruation. Because the dose of progesterone in emergency contraceptive pills is relatively high, much higher than that in short-acting contraceptive pills, it may affect the menstrual cycle, and irregular vaginal bleeding, withdrawal bleeding, delayed or absent menstruation may occur. The effects of emergency contraceptive pills on menstruation may even last for 3-6 months, as emergency contraceptive pills mainly work by delaying ovulation, thus achieving a remedial effect. In addition, emergency contraceptive pills may have adverse effects on liver and kidney function, as well as gastrointestinal adverse effects such as dizziness, nausea, and regurgitation, which may even affect the success rate of the remedy.