Oral contraceptive pill is a highly effective method of contraception and its ingredients are usually estrogen and progesterone. It achieves its contraceptive effect by inhibiting ovulation, changing the nature of cervical mucus, altering the morphology and function of the endometrium and changing the function of the fallopian tubes. At present, oral contraceptives constitute different formulations and preparations due to different hormonal components, and the methods of taking various oral contraceptives are different. Below, we understand the common oral contraceptive pill taking time. 1.Compound short-acting oral contraceptives composed of estrogen and progesterone composite preparations, the method of taking the following: Compound norethindrone tablets (contraceptive tablets No. 1), compound medroxyprogesterone tablets (contraceptive tablets No. 2): in the menstrual period on the fifth day of the beginning of the drug, 22 days of continuous service, stopping the drug after 7 days of the second cycle of service. Compound Deferiprogesterone Tablets (Maflon), Drospirenone Ethinyl Estradiol Tablets (Yosmin), Ethinyl Estradiol Cyproterone Tablets (Dayin 35): take the medication on the 1st day of menstruation for 21 days, and take the medication for the 2nd cycle after 7 days of withdrawal. If you miss a dose, you need to make up a tablet in the next morning, at this time, be alert to the possibility of pregnancy; if you miss 2 tablets, make up the dose to be added at the same time with other contraceptive measures; miss 3 tablets should be discontinued, to start taking the next cycle of medication after bleeding. 2, there is also an oral contraceptive pill for emergency contraception, it is used for unprotected measures taken after sexual intercourse, not as a regular contraceptive measures. At present, there are three main types of commonly used emergency contraceptives: estrogen-progestin composite (compound levonorgestrel), simple progestin drugs (levonorgestrel) and anti-progestin drugs (mifepristone). Compounded levonorgestrel short-acting oral contraceptives: 4 tablets taken orally within 72 hours of intercourse, repeated 12 hours later. Levonorgestrel: a progestogen-only medication taken as early as 0.75mg within 72 hours of intercourse, repeated 12 or 24 hours later; these 2 doses may also be taken as a single dose, i.e., 1.5mg of levonorgestrel. Mifepristone: 10mg or 25mg as early as possible within 120 hours of intercourse.