Objective: To study the effect of Huanglian Jiedu Tang (HJT) in the reversal effect of drug resistance in Escherichia coli. Method: E. coli with extended-spectrum β-lactamase is screened by disc diffusion method. The minimum inhibitory concentration of HJT was determined.The extended-spectrum β-lactamase enzyme E. coli was cultured with a HJT concentration lower than the minimum inhibitory concentration. The cultivation duration and optimal concentration for reversal effect were selected

and the reversal rate was determined. Result: Minimum inhibitory concentration of HJT to the E. coli ATCC8099 was 0.6 g·L-1. The cultivation duration was 30 h and the optimal concentration for reversal effect was 0.3 g·L-1.The reversal rate of ampicillin was 60.0%. The reversal rate of ceftazidime was 66.7%. The reversal rate of cefmetazole was 75.0%. The reversal rate of ceftriaxone was 66.7%. Conclusion: The effect of HJT for reversal drug resistance in E. coli is defined. It is a way to reverse drug resistance in E. coli.