Goniopedaline, a new phenanthrene lactam, aristololactam A-II and its N,O-diacetyl derivative, taliscanine (second natural occurrence), aurantiamide acetate and β-sitosterol and its β-D-glucoside have been isolated from the leaves and twigs of Goniothalamus sesquipedalis. The structure of goniopedaline has been established from its spectral evidence as 10-amino-3-hydroxy-2,4-dimethoxyphenanthrene-1-carboxylic acid lactam. The structures of aristololactam CII, CIII, DII and DIII have been revised from the previously suggested 3-hydroxymethyl-2-methoxy derivatives and the 3-carboxy-2-hydroxy derivatives to the 2-hydroxymethyl-3-methoxy derivatives and the 2-carboxy-3-hydroxy derivatives respectively based on a careful analysis of their ¹³C NMR spectral data. Thus, goniopedaline is the only 2 oxygenated aristololactam known so far. This constitutes the first report of the phenanthrene lactams from the Goniothalamus genus.