Compound oral contraceptive pill (COC) is a more efficient and simple contraceptive method nowadays. Its active ingredients are progesterone and estrogen, and its mechanism of action is to inhibit the hypothalamus-pituitary-ovary axis (H-P-O axis), thus inhibiting the cyclic synthesis and release of pituitary gonadotropins, and then inhibiting follicle development and maturation in the ovaries, and ultimately inhibiting ovarian ovulation and thus achieving contraceptive effect. At the same time, it also acts against androgens and inhibits endometrial hyperplasia. But in addition to the function of contraception, what are the other roles of birth control pills? First, improve dysmenorrhea: dysmenorrhea refers to the lower abdominal pain, swelling before and after menstruation or menstruation, accompanied by lumbago or other discomfort, the symptoms seriously affect the quality of life. Ninety percent of dysmenorrhea is primary, and studies have shown that the major cause of primary dysmenorrhea is high levels of prostaglandins. High levels of prostaglandins occur during ovulation, causing ischemia of the uterine muscles and uterine contractions leading to dysmenorrhea. COC can reduce the thickness of endometrium and inhibit ovulation, and can also reduce the secretion of prostaglandin through negative feedback, so as to relieve dysmenorrhea or make dysmenorrhea disappear. Dysfunctional uterine bleeding (dysfunctional hemorrhage): dysfunctional hemorrhage refers to abnormal uterine bleeding due to the malfunction of the regulatory mechanism of the neuroendocrine system, which is mainly manifested as frequent and scanty menstruation, and excessive, scanty and irregular menstrual bleeding. Merit blood is divided into anovulatory and ovulatory type, anovulatory functional uterine bleeding accounted for 70% ~ 80%, mostly seen in puberty and perimenopause, in the exclusion of organic lesions of the reproductive tract, the contraceptive pill can be used to stop bleeding, in which estrogen by maintaining the growth of the endometrium, increase the thickness of the endometrium, to prevent breakthrough bleeding and bleeding, and progesterone through the protection of the endometrium so that the secretion of the endometrial glands, interstitial metaphylactic-like atrophy and hemostasis. Therefore, for pubertal dysfunctional uterine bleeding, COC is generally used to stop bleeding, while perimenopausal dysfunctional uterine bleeding should be stopped by using progesterone to make the endometrium atrophy. Endometriosis: The main symptoms of endometriosis are pain and infertility, and its treatment principle is mainly based on surgery, supplemented by drugs, and inhibiting ovarian function is the best drug treatment. COC inhibits ovarian ovulation by suppressing the H-P-O axis, thus lowering the level of estrogen, making the ectopic endometrium atrophy, necrosis and absorption, so as to achieve the effect of treating and relieving dysmenorrhea. During use, there is withdrawal bleeding once a month, which relieves pain and stops the progression of the disease, as well as contraception. Therefore, it is suitable for those who have children or do not want to have children, but ovulation and fertility can be resumed after stopping the drug. American scholars of obstetrics and gynecology suggest that: endometriosis can be long-term cyclical use of oral contraceptives after surgery, but it is best to make a routine physical examination once a year. Adenomyosis: Adenomyosis is a clinical syndrome in which the endometrium infiltrates benignly into the myometrium and grows diffusely therein, with excessive menstrual flow, prolonged menstrual period and progressively aggravated progressive dysmenorrhea as the main manifestations.COC can inhibit ovulation, reduce estrogen level, and maintain estradiol at the level of early follicular phase, so that the ectopic endometrial foci in the myometrium will atrophy in different degrees and the function will decrease, thereby Relieve the symptoms of dysmenorrhea and prevent the development of the lesions. If fertility is not required, it can be used for a long period of time, but patients should be observed and followed up: including lesions, blood lipids, blood coagulation, liver and kidney function, and whether there is recurrence after stopping the drug. Polycystic ovary syndrome (POCS): POCS is a group of clinical syndromes with unknown etiology, highly heterogeneous clinical manifestations, anovulation and hyperandrogenemia as the main features.COC can inhibit the hypothalamus-pituitary-ovary axis to reduce the size of the ovary; prevent the endometrium from proliferating too long and control the menstrual cycle to make it regular; inhibit the production of androgens to reduce the activity of androgens and elevate the plasma sex hormone binding capacity. Elevate plasma sex hormone binding globulin (SHBG), so that free testosterone, dehydroepiandrosterone (DHT) down, thus reducing androgen production and circulating androgen levels and activity, to fight against peripheral hyperandrogenic signs, so that acne, hirsutism can be improved; protection of the endometrium, to counteract the role of a single oestrogen on the endometrium; so as to achieve the purpose of alleviating the polycystic ovary syndrome.