Objective To study the active parts of Peristrophe japonica of vaginitis treatment effect. Methods The bacterial vaginitis model was established by injecting the bacteria of Staphylococcus aureus and Escherichia coli into the vagina of the mice and the treatment effect of each extract of Peristrophe japonica was observed. Results Three drug administration groups (including water extract of Peristrophe japonica, ligarine fraction and 70% ethanol fraction) showed marked treatment effect on the vaginitis models. The effect of water extract of Peristrophe japonica group were stronger than that of the ligarine fraction and 70% ethanol fraction groups. The pathogens seroconversion rates in Staphylococcus aureus were orderly as follows: 60%, 50%, 40%. The pathogens seroconversion rates in Escherichia coli were orderly as follows: 80%, 70%, 50%. Conclusion The ligarine fraction and 70% ethanol fraction of Peristrophe japonica might be the active extracts of curing vaginitis.