Two pairs of dihydrobenzophenanthridine alkaloid, named (+/-)(S)-6-((R)-1-hydroxyethy) dihydrochelerythrine (la, lb) and (+/-)(S)-6-((R)-1-hydroxyethyl)dihydro-sangunarine (2a, 2b) were isolated from the root of Macleaya cordata. Their chemical structures were elucidated by analysis of the spectroscopic data including onedimensional (1D) and two-dimensional (2D) NMR spectra, and were further confirmed by X-ray crystallographic analysis.