Metronidazole suppositories can be used for 3 consecutive courses of treatment, but the middle needs to be spaced out for a period of time, so as not to cause disruption of the flora in the vagina. Generally, it is used 2-3 days after the end of menstruation, and it is used continuously for 7-10 days, which belongs to 1 course of treatment. Wait until the end of the next period and then continue to use 7-10 days, belong to the second course of treatment, and so on for 3 consecutive courses of treatment. Metronidazole belongs to nitroimidazole antibacterial drugs, on anaerobic bacteria, amoeba, trichomonas and other killing effect, clinically used for vaginal trichomoniasis, can also be used to prevent post-surgery anaerobic infections. Adverse reactions and contraindications to the use of the drug are not clear. Non-pregnant and lactating women are prohibited. Caution should be taken to abstain from alcohol during administration, as this may lead to the development of disulfiram-like reactions. Patients must use the drug under the supervision of a specialized physician and strictly follow medical advice.