Estriol has the effect of promoting the proliferation of cells in the reproductive tract, and specifically works as a hormone replacement therapy for symptoms of genitourinary tract discomfort caused by estrogen deficiency. After menopause, the vaginal wall shrinks, the mucous membrane becomes thin, and the local resistance is reduced, thus easy to be infected by other pathogenic bacteria, resulting in inflammation. At this time, patients can use estriol to supplement the body’s estrogen, which can alleviate the symptoms of vulvar itching, burning discomfort, abnormal discharge and so on. During the use of estriol patients may experience breast discomfort and pain, skin nodular erythema, ovarian cancer and other adverse reactions, suffering from breast cancer, estrogen-dependent malignant tumors, acute liver disease and other patients are prohibited from using the drug. It is recommended that patients should use estriol under the guidance of a doctor and avoid unauthorized use of the drug to avoid adverse effects.