There are many microorganisms in the vagina under normal conditions, however, these microorganisms are dependent on each other and restrain each other to achieve a dynamic ecological balance and do not cause disease. However, in case of micro-ecological imbalance in the vagina, these bacteria will grow and multiply and vaginitis will occur. Most of the vaginal microecological imbalance is caused by the decrease of lactobacilli in the vagina. The decrease of vaginal lactobacilli is mostly due to frequent sexual intercourse, vaginal irrigation or too many sexual partners, which leads to the increase of vaginal pH, which is not conducive to the growth of lactobacilli, so it leads to bacterial vaginosis. In addition, long-term application of antibiotics can also inhibit the growth of lactobacilli.