OBJECTIVE:To establish a method for the simultaneous determination of chloramphenicol and dexamethasone sodium phosphate in ear drops by HPLC METHODS:Chloramphenicol and dexamethasone sodium phosphate were separated with a mobile phase of methanol-phosphate buffer solution(0 34% KH2PO4 solution)(60∶40,v/v,1 0ml/min)on Kromasil C8 column and detected at 240nm RESULTS:Good linearity appeared in the concentration of chloramphenicol 100～500?g/ml,r=0 9 999,the recovery was 98 5%～100 8%,RSD≤1 5%;and good linearity showed in the concentration of dexamethasone sodium phosphate 16～80?g/ml,r=0 9 990,the recovery was 98 8%～100 6%,RSD≤2 0% CONCLUSION:This method can simultaneously detect both ingredients in the ear drops