The side effects of taking emergency contraceptive pills over 40 years old mainly include: menstrual disorders, irregular vaginal bleeding, endocrine disorders, liver and kidney function damage and so on. 1. Menstrual disorders: Emergency contraceptive pills are mainly used to prevent ovarian ovulation, so it is possible to cause menstrual disorders after taking emergency contraceptive pills. 2. Irregular vaginal bleeding: after taking emergency contraceptive pills, the hormone levels in the body may fluctuate, resulting in the shedding of the uterine lining, which may lead to irregular vaginal bleeding. 3. Endocrine disorders: Emergency contraceptive pills contain a large amount of progesterone, and women over 40 years of age themselves, due to the gradual decline of ovarian function, the amount of sex hormones secreted will gradually decrease, and if you suddenly take a large number of drugs containing progesterone, it may lead to endocrine disorders. 4. Liver and kidney function damage: emergency contraceptive pills contain a large amount of progesterone, women over 40 years old metabolic function is poor, so it may cause liver and kidney function damage. In short, women over 40 years old are not recommended to take emergency contraceptive pills, it is recommended to take scientific contraceptive methods, such as: condoms, birth control rings and so on.