Increased leukorrhea with fishy odor is considered bacterial vaginitis. Bacterial vaginitis is a mixed infection caused by a dysbiosis of the normal vaginal flora, which is characterized by increased vaginal discharge with a fishy odor, aggravated by sexual intercourse, and may be accompanied by mild vulvar itching or burning. The fishy odor of the discharge is mainly due to the proliferation of anaerobic bacteria and the production of ammonia. The discharge is grayish white, uniform and often adheres to the vaginal wall, but the viscosity is very low and the discharge can be easily swabbed out of the vaginal wall. The principle of treatment is to use anti-anaerobic drugs, mainly metronidazole and clindamycin. Metronidazole can inhibit the growth of anaerobic bacteria and does not affect the growth of lactobacillus, so it is the ideal drug for treatment.