Eight sesquiterpenes, four stilbene derivs. along with two lignans have been isolated from lipophilic fraction of stems of Dendrobium moniliforme (Orchidaceae). Among the eight sesquiterpenes, one allo-aromadendrane-type (I) and four picrotoxane-type sesquiterpenes (e.g. II) were identified to be new compds., and alpha -dihydropicrotoxinin was isolated as a new natural product. Their structures were established on the basis of spectroscopic anal. [on SciFinder (R)]