The short-acting pill has the least side effects in terms of the magnitude of side effects. However, for the contraceptive effect of the pill, different drugs have their own different use and the best choice should be made according to the needs. There are three types of birth control pills: short-acting, long-acting, and emergency pills. Many people choose emergency contraceptive pills to remedy the situation when there are no contraceptives around, but they often ignore the side effects and safety risks of contraceptive pills. In the end, the choice of which contraceptive pill is safer and more effective, is the more concerned about many people. 1, short-acting contraceptive pills: compared with other types of contraceptives, short-acting contraceptives are safer. The short-acting contraceptive pill has low estrogen and progestin content and fast metabolism. Therefore, the side effects are relatively small compared to other contraceptives, and even if there are side effects, they will generally disappear slowly within 24 hours of stopping the pill. But because the short-acting contraceptive pill has a short release time, it needs to be taken in cycles of 28 days as prescribed by the doctor, usually taking 21 days, stopping for 7 days, and then entering the next cycle. 2. Long-acting contraceptive pill: The side effects of the long-acting contraceptive pill are greater than those of the short-acting pill, but smaller than those of the emergency contraceptive pill. Because the hormone content of long-acting contraceptives is larger, so the metabolism time is long and the adverse reactions are larger. In addition, long-acting contraceptives should not be stopped suddenly, but must be changed to short-acting contraceptives for three months so that the hormone level in the body slowly decreases to the normal range before stopping the pill. Irregular vaginal bleeding, less menstruation, weight gain, and even amenorrhea are all possible adverse reactions to long-acting contraceptives, but generally disappear after a period of discontinuation. 3, emergency contraceptives: emergency contraceptives are the three types of contraceptives with the greatest side effects, and are not recommended as a daily contraceptive measure in non-special cases. The main component of the emergency contraceptive pill is highly effective progestin, the hormone content is greater than the other two, taking the emergency contraceptive pill may appear menstrual disorders, obesity, nausea, vomiting, dizziness, fatigue and other side effects. To sum up: both the short-acting contraceptive pill, which is the safest of the three, and the emergency contraceptive pill, which has the most side effects, are not 100% safe. It is recommended that women use condoms and birth control devices for daily contraception to reduce the impact of the pill on the body. If you have to use the pill, it is recommended to use the relatively safe short-acting contraceptive pill, and to stop it in time if you have adverse reactions; for emergency unprotected sex, if there is no need for pregnancy, you should still use the emergency contraceptive pill for contraception.