Two minor coumarins, including a new compound qianhucoumarin J, were isolated from Peucedanum praeruptorum by a multi-step separation procedure using high-speed counter-current chromatography (HSCCC) and preparative high performance liquid chromatography (prep-HPLC) monitored by high performance liquid chromatography coupled with mass spectrometry (HPLC/MS) analysis. The crude extract was analyzed first by HPLC/MS to detect unknown compounds. The target compounds were enriched by HSCCC, using a two-phase solvent system of petroleum ether-ethyl acetate-methanol-water (5:5:6:4, v/v) and then isolated and purified by preparative HPLC monitored by HPLC/MS. The structure of the new compound was elucidated mainly by analysis of its 1D and 2D NMR spectral data. Its absolute configuration was determined by chemical degradation followed by chiral HPLC analysis. (C) 2010 Elsevier B.V. All rights reserved.