The flow of leucorrhea in girls is generally normal, indicating that the ovaries have ovulation function, which is one of the signs of entering puberty and development. Leukorrhea is a vaginal secretion, which is a mixture of vestibular gland, cervical gland, endometrial secretion, exudate of vaginal mucosa and shed vaginal epithelial cells, and is related to estrogen changes. The leukorrhea is generally white and thin, with small amount and no odor. It is called physiological leukorrhea, which can keep the vagina moist and reduce the frictional damage to the front and back walls of the vagina. Near the time of ovulation, the leucorrhea increases and is transparent, thin and egg-white like, with a high degree of lacrimation. Two to three days after ovulation, the leucorrhea is sticky and the amount is low. Women should usually pay attention to pubic hygiene, wash properly and change their underwear regularly. Leukorrhea contains lactobacillus, lysozyme and antibodies, which can inhibit the growth of bacteria. Therefore, girls should be alert when they have abnormal leukorrhea, such as high volume, yellow color and foul odor, accompanied by vulvar itching, pain and painful urination. Tofu-like changes in the leucorrhea suggest mycosis fungoides. Foamy leucorrhea with foul odor is considered trichomonas vaginalis. In case of bloody leucorrhea, cervicitis, uterine fibroids, cervical cancer and other diseases cannot be excluded.