A new indol alkaloid along with 17 known compounds were isolated from the seeds of Rheum maximowiczii Losinsk (Polygonaceae). Its structure was elucidated from the 2D NMR and other spectral evidence. Several of these compounds were screened for cytokine-inducing activity on human peripheral blood mononuclear cells. The cytokine-inducing activity of some of the isolated compounds is also reported.