Abstract: Simultaneous determination of six ephedrines in urine sample has been achieved byhigh performance liquid chromatography on a Lichrospher RP-18 column ,using methylamphetamineas internal standard.The 6 epedrines are well separated in 25 minutes with resolution better than1.8.This method has high recovery ,selectivity and reproducibility,and the linearity is satisfactoryfrom l.5μg/ml to 25μg/ml with correlation coefficients better than 0.999。