Chlorogenic acid was extracted from flos lonicerae by using one-step-method. The solvent was a mixed solutioin of ethyl acetate and 0.05 mol/LHCl. The effect of the volume fraction of ethyl acetate, tempeature and time on the extraction of chlorogenic acid was studied. The antimicrobial abilities of chlorogenic acid were also studied. The optimum conditions are: the volume fraction of ethyl acetate, 0.8; the temperature, 65°C;and time, 3 h. The mass ratio of the product to flos lonicerae is 3.21%, and the purity of chlorogenic acid is 86.3...