In modern society, 75% of all women in the world have had vaginitis at least once in their lives. The vagina has a dynamic microbial “ecosystem” with varying vaginal pH levels. An imbalance in this ecosystem can alter vaginal pH and tip the scales to the point of causing problems, such as vaginitis, that require medical attention. Although vaginitis is not an incurable disease, it causes discomfort and pain that disrupts women’s daily life. The most common causes of vaginitis include bacterial vaginosis, trichomoniasis, and vulvovaginal candidiasis. The vagina normally has a unique flora that maintains the internal physical and chemical environment. The presence of normal flora depends on the maintenance of various components of the pH balance, which is in dynamic equilibrium. The normal vaginal pH for women of childbearing age ranges from 3.8 to 5.0, which is moderately acidic. The normal vagina is covered with a thin layer of clear fluid known as vaginal fluid. Many factors can cause changes or imbalances in vaginal pH, including vaginal infections, aging, sexual activity, and vaginal douching. The general vaginal microbiome (lactobacillus species) can produce an acidic pH and bacteriocins that kill other bacteria in the vagina. Lactobacilli can produce an acidic environment in the vagina that is designed to protect women from sexually transmitted pathogens and opportunistic infections. If this normal flora such as lactobacilli is absent or greatly reduced, the vaginal ecosystem will become imbalanced and other microorganisms or bacteria in the vagina can proliferate, leading to vaginitis. There are different types of vaginitis, including bacterial vaginosis, vaginal candidiasis, trichomoniasis, and aerobic vaginitis. Bacterial vaginosis is diagnosed by the presence of a homogeneous milky vaginal discharge, vaginal pH above 4.5. Abnormal pH values ​​increase the possibility of vaginitis, and vaginal pH measurement is used for initial screening. Research data shows the importance of the pH value. Vaginal fluid pH values ​​of 4–4.5 or less indicate no vaginitis, while pH values ​​above 4.5 indicate vaginitis and bacterial vaginosis. However, with a Trichomonas vaginalis infection, the pH may rise to 6.5 or more. The pH level associated with the vagina is called the “vaginal pH value” and plays a valuable role in determining vaginal health. A lower pH value (more acidic) in the vagina than blood or interstitial fluids can protect the vaginal mucosa from pathogenic organisms. Vaginal pH can be affected by overall health, including age, vaginal hydration status, daily diet, and safe sex. The value of vaginal pH depends on age. The normal value of vaginal pH for a woman of reproductive age ranges from 4.0 to 4.5, but the value can be slightly higher than 4.5 in premenarcheal and postmenopausal women. Vaginal pH value obviously plays an important role in vaginal health, but it is important to note that maintaining a healthy vaginal pH is characterized by the metabolism of Lactobacillus acidophilus and other endogenous flora, estrogen, glycogen and existing flora and pathogens. Vaginal microorganisms are the main stabilizers of the vaginal ecosystem. Lactobacillus acidophilus is a microorganism that can ferment glycogen obtained from the breakdown of eutrophic vaginal mucosa into lactic acid and subsequently release hydrogen ions. The result of this metabolism is an acidic pH of 4–4.5, and the resulting acidic vaginal environment provides a protective effect. It creates a barrier that prevents the unhealthy microbiome from multiplying too quickly and causing infection. An imbalance in this ecosystem can cause abnormal vaginal pH and can be used to determine the presence of bacterial pathogens as well as menopausal status. Studies have confirmed that an increase in vaginal pH can lead to bacterial vaginosis and spontaneous preterm births in pregnant women. Vaginal pH value has a profound impact on women’s lives. Maintaining a normal vaginal pH can be used to effectively manage and prevent infection. References: 1. Larsen B. Vaginal flora in health and disease. Clin. Obstet. Gynecol. 2. Carr PL, Felsenstein D., Friedman RH Evaluation and management of vaginitis. J.Gen. Intern. Med. 3. Murta EF, Filho AC, Barcelos AC Relationship between vaginal and endocervical pH in pre- and post-menopausal women. Arch. Gynecol. Obstet. 2005Maintaining a normal vaginal pH can be used to effectively manage and prevent infection. References: 1. Larsen B. Vaginal flora in health and disease. Clin. Obstet. Gynecol. 2. Carr PL, Felsenstein D., Friedman RH Evaluation and management of vaginitis. J.Gen. Intern. Med. 3. Murta EF, Filho AC, Barcelos AC Relationship between vaginal and endocervical pH in pre- and post-menopausal women. Arch. Gynecol. Obstet. 2005Maintaining a normal vaginal pH can be used to effectively manage and prevent infection. References: 1. Larsen B. Vaginal flora in health and disease. Clin. Obstet. Gynecol. 2. Carr PL, Felsenstein D., Friedman RH Evaluation and management of vaginitis. J.Gen. Intern. Med. 3. Murta EF, Filho AC, Barcelos AC Relationship between vaginal and endocervical pH in pre- and post-menopausal women. Arch. Gynecol. Obstet. 2005