If, in clinical practice, metronidazole suppositories are used to treat vaginal inflammation and are inserted into the vagina, itching may occur for the following reasons: first, an allergic reaction to the drug. When there is an allergic reaction to this drug, the vaginal mucosa becomes red and swollen, followed by severe itching. It is clinically recommended to stop the treatment with this drug. If the allergy is severe, it can be treated with anti-allergy medication and other medications can be used to continue the treatment of vaginal inflammation. Secondly, if you do not wash your vulva well or wash your hands during the medication process, you may bring in pathogenic bacteria, especially Candida, when you insert the medication, which may cause a Candida infection in the vagina, resulting in a local inflammatory reaction with an allergic reaction and more itching.