Bacterial vaginosis, a mixed endogenous infection caused by a decrease in Lactobacillus and an increase in Gardnerella and anaerobic bacteria in the vagina. The cause of the change in vaginal flora remains unclear and it is speculated that it may be related to frequent sexual intercourse, multiple sexual partners or alkalinization of the vagina by vaginal irrigation. In addition to causing vaginal inflammation, bacterial vaginosis can also cause other adverse outcomes, such as bacterial vaginosis during pregnancy, which can lead to chorioamnionitis, premature rupture of membranes, and preterm delivery; in non-pregnant women, it can cause endometritis, pelvic inflammatory disease, and infection of the vaginal dissection after hysterectomy. The main symptoms are increased vaginal discharge with fishy odor, especially after sexual intercourse, accompanied by mild vulvar itching or burning sensation, and fishy odor due to anaerobic bacteria reproduction and ammonia production. The discharge is grayish white, uniform, thin and often adheres to the vaginal wall, but the viscosity is low and the discharge can be easily swabbed away from the vaginal wall. Clinical diagnostic criteria are vaginal discharge characteristics, positive clue cells, ph over 4.5, and 3 out of 4 positive amine odor tests. The principle of treatment for bacterial vaginosis is the use of anti-anaerobic drugs, mainly metronidazole, tinidazole and clindamycin. Metronidazole inhibits the growth of oxybacteria and does not affect the growth of Lactobacillus, which is a more desirable therapeutic drug, but is less effective against mycoplasma. Although the disease is associated with multiple sexual partners, the treatment given to sexual partners did not improve the treatment effect and reduce its recurrence, so sexual partners do not need routine treatment. Recurrence of bacterial vaginosis is common and patients with persistent or recurrent symptoms need to be seen again for treatment, either with different anti-anaerobic drugs than the initial treatment or with Lactobacillus vaginalis preparations.