Metronidazole suppositories are used to treat vaginitis and are often used when suffering from gynecological inflammation, and the depth of administration is usually recommended to be one finger deep. Metronidazole suppositories can be useful even if they are not inserted deeply, but if they are inserted shallowly, it may affect the effectiveness of the medication and prolong its use. Under normal circumstances, it is recommended to place the metronidazole pessary as deep as possible into the vagina, at the junction of the vagina and the cervix, mainly to allow deeper tissues to reach the medication and to prevent it from falling out. The normal vaginal opening will discharge some secretions such as leukorrhea. If the medication is placed too shallowly, it may be discharged from the vagina with leukorrhea during daytime work activities, walking, running, or even exercising, thus affecting the effectiveness of the application. Therefore, metronidazole suppositories are recommended to be used every night before bedtime to prevent dislodgement to a certain extent and to make it less likely to forget the medication. Patients are advised to go to the hospital promptly after the symptoms of vaginitis appear and use the medication as prescribed by the doctor, not to use the medication blindly to avoid aggravating the original condition with the wrong medication.