Endocrine therapy for breast cancer is long and takes place over 5-10 years, with side effects occurring during the treatment period and disappearing when the treatment is over. Many women with breast cancer have immunohistochemistry that suggests estrogen receptor progesterone receptor positivity, and this type of breast cancer often requires endocrine therapy, which often takes 5-10 years. There are 3 main side effects of this drug and will remain with the treatment. One is the possibility of menopausal symptoms, mainly hot flashes and irritability, the second is the possibility of joint pain, osteoporosis and calcium loss, and also abnormal lipid metabolism, which can lead to hyperlipidemia, a side effect that only disappears when treatment is stopped. In addition endocrine therapy for breast cancer may cause gynecological disorders such as thickening of the uterine lining. Patients should follow medical advice when undergoing endocrine therapy, as the benefits outweigh the drawbacks in terms of tumor control.