The most common cause of leukorrhea is bacterial vaginosis, which is characterized by thin leukorrhea with a large volume, yellowish color and a distinctive fishy odor of vaginal discharge. 2. Cancer of the fallopian tubes, which is characterized by watery leukorrhea and no odor. The main feature is that the leucorrhea is like water, and there is no odor, and often there is a lump in the lower abdomen, and the presence of a mass in the fallopian tube can be detected by ultrasound. 3, caused by cancer of the endometrium, not only is the leucorrhea thin, but there is also a very bad odor. In addition, it is also seen in cervical cancer with bloody leukorrhea and a foul odor.