There are many causes of vaginitis, most of which are due to sexual activity. During sexual activity, the normal environment of the vagina can be altered. The vagina contains normal bacteria and has a relatively high acidity. If there is sexual activity, the pH balance inside the vagina can change, allowing pathogenic bacteria to proliferate, thus making it easy to develop vaginitis. Additionally, poor personal hygiene can also lead to vaginitis, such as using damp sanitary products and not changing underwear promptly. Therefore, it is essential to maintain hygiene during sexual activities and to keep the external genital area clean, wearing breathable, cotton underwear.