A novel phenanthrene compound, diphenanthrin (1), and an undescribed alkaloid compound, N- chloromethylstephenanthrine (2), together with two known compounds (3-4) were isolated from the EtOH extract of the roots of Stephania tetrandra. Their structures were elucidated by 1D and 2D NMR, mass spectroscopy and comparison of NMR data with those of known compounds. In anti-inflammatory assay, compounds 3 and 4 showed the inhibitory effects on NO production, with IC50 values of 41.51 +/- 0.20 and 23.87 +/- 2.12 mu M.