Although most vaginitis is caused by a single cause, such as simple fungal vaginitis or simple bacterial vaginosis, it is not uncommon to see a combination of infections causing multiple vaginitis at the same time. The most common is trichomoniasis combined with bacterial vaginitis caused by a combination of trichomonas and anaerobic bacteria. Infectious vaginal inflammation combined with nonspecific vaginitis (allergic inflammation due to exposure to allergenic substances) can also be seen clinically. Whether it is a complex vaginal inflammation caused by a combination of infections or a vaginal inflammation caused by infection + allergy, the principle of treatment is to address the different causes at the same time. For example, if you have both fungal and trichomonas infections, then you need to treat with both antifungal drugs and metronidazole (also known as methotrexate); when anaerobic vaginitis is combined with vulvar contact inflammation, you need to treat with both metronidazole and anti-allergy drugs (such as hormone ointment). Peng Peng, Department of Gynecology, Peking Union Medical College Hospital