Normal leucorrhea is milky white and has no odor or a faint fishy smell. If the leukorrhea is dark brown, the most common cause is due to the following reasons: the first is a local lesion of the cervix, resulting in local capillary rupture and bleeding, and this bleeding is not discharged outside the vagina in time and becomes old bleeding, which is dark brown when it is discharged from the vagina. The second is due to endometrial lesions. Since the endometrium is affected by hormone levels and inflammation, when hormone levels change or when there is inflammation and lesions in the endometrium, the endometrium bleeds and the bleeding accumulates in the uterine cavity and then flows out of the uterine cavity, it turns into dark brown leukorrhea. The third one is caused by pelvic tumor, when there is a tumor in the pelvic cavity, it will also cause changes in the endometrium, causing local bleeding, which will result in dark brown leucorrhea. Therefore, it is recommended to do a detailed examination and give treatment according to the results.