Seven stilbenoids were isolated from stems of Dendrobium plicatile and their structures were elucidated on the basis of spectroscopic data. Six of them were known compounds, 3-methoxy-3',5-dihydroxybibenzyl, 3,3',4'-trimethoxy-5-hydroxybibenzyl, 2-methoxy-4,7-dihydroxy-9,10-dihydrophenanthrene, 2,4-dimethoxy-3,7-dihydroxyphenanthrene, 3,4-dimethoxy-2,7-dihydroxy-9,10-dihydrophenanthrene and ephemeranthoquionone. The seventh, 2,2'-dimethoxy-4,4',7,7'-tetrahydroxy-9,9',10,10'-biphenanthrene, was a new dimer. Copyright (C) 1996 Elsevier Science Ltd