A new picrotoxane-type sesquiterpene, findlayanin (1), was isolated from Dendrobium findlayanum with crystallinin (2). The structure of compound 1 was established to be (1R,2S,3R,4S,5R,6S,9R)-2,3,11,12-tetrahydroxypicrotoxan-12(15)-lactone by spectroscopic methods.