Minimal inhibitory concentrations ( MIC) of folium isatidis, bark of Rhus chinensis Mill, essential oil of herba scutellariae barbatae and levofloxacin aganist 139 strains bacteria were determined by agar dilution method. 用琼脂稀释法测定大青叶、盐肤木树皮水煎液、半枝莲挥发油3种中药及左氧氟沙星对139株微生物的最低抑菌浓度(MIC)。