Amenorrhea is defined as the absence of menstruation for six months or the cessation of menstruation for more than three cycles according to one’s original menstrual cycle. The cause of amenorrhea must be found before treatment can be given. Menstruation is mainly regulated by the endocrine system of the hypothalamic-pituitary-ovarian axis, but any problem with these three can cause amenorrhea, as well as other causes, such as repeated uterine operations: abortion, curettage, etc. that lead to endometrial damage. If the sudden amenorrhea is mostly due to hypothalamic causes, such as a great emotional shock, chronic mental overstrain, excessive weight loss, etc., it can also be due to long-term use of special medications and diseases of the endocrine system: hypo- or hyperthyroidism, hyperprolactinemia due to pituitary tumors, etc. If it is not due to endothelial damage it can be treated by hormone supplementation. If it is caused by endocrine diseases it is recommended to treat the underlying disease first, such as pituitary tumor removal, taking medication to control thyroid function, etc. Another common disease is polycystic ovaries, which can be treated with oral short-acting contraceptives, the first line of which is Daimler 35. There are many causes of amenorrhea, and it is not possible to generalize. It is important to find out the cause of amenorrhea for individualized treatment.