Abstract: Perilla ketone is a potential lung toxin to laboratory-used animals.A new method for preparative separation of perilla ketone from the leaves of Perilla frutescens by high speed countercurrent chromatography(HSCCC) was established to evaluate the possible hazards to human health.The results showed that HSCCC was an efficient tool in the separation of perilla ketone.A mixture of hexane,ethanol and water in the ratio of 6:5:1 was used as the solvent system,which was shaken in a separatory funnel,and after settling for phase separation,the upper one was taken as the stationary phase,and the lower one as the mobile phase.The mobile phase was operated at a flow rate of 1.2 mL/min,while the apparatus rotated at 800 r/min.After the proceeding separation for 6 hours,28.0 mg of perilla ketone was obtained with a purity of 98.8% determined by gas chromatography in one step elution from 1 g crude extract,and the identification was performed by nuclear magnetic resonance(¹H-NMR、¹³C-NMR and DEPT-NMR).