Abstract: The assay was to study the sensitivity of the pathogenic Escherichia coli from ostrich to ciprofloxacin combined with baicalin. First, ciprofloxacin and baicalin against Escherichia coli from ostrich were detected by double dilution method, the resistant Escherichia coli from ostrich were T1 to T4, T7,T8,T10,T12,T21,T25. Then Escherichia coli from ostrich were induced broth dilution checker-board method, when ciprofloxacin and baicalin were used alone, the MIC were 64, 512 or 1024 μg/mL,respectively, when the use of ciprofloxacin and baicalin were combined, the fractional inhibitory concentrations (FIC) of Escherichia coli from ostrich (T1，T2，T3，T7，T8，T10，T12 and T21) were all 0.375, the FICs of Escherichia coli from ostrich (T4，T25) were both 0.25, all were below 0.5. The results suggested that the combination of ciprofloxacin and baicalin demonstrated synergistic effect on the Escherichia coli from ostrich.

Key words: ciprofloxacin; baicalin; Escherichia coli from ostrich; combined susceptibility test; fractional inhibitory concentration (FIC)