Metronidazole pessary once put vagina itch can be considered to have an allergic reaction or hygiene problems caused by, you can change the drug, pay attention to clean and other ways to treat. 1. Allergic reaction: if the metronidazole suppository into the vagina after the itchy situation may be allergic to the drug, it is recommended to stop using this kind of drug, replace the other anti-allergic drugs to give the appropriate treatment. 2. pay attention to clean: in the process of using the drug is not good to wash the vulva or hand washing, in the plugging of the drug will make the pathogenic bacteria into, especially candida, will make the vagina Candida infection, causing local inflammatory reaction, accompanied by allergic reaction will appear more itchy, so pay attention to hand hygiene and cleanliness. Note that if the itch is very strong need to consult a gynecological examination to determine the cause of the formal treatment.