A small quantity of a new alkaloid, designated wilforzine, has been isolated from the roots of Tripterygium wilfordii by partition chromatography employing ultraviolet absorbancy ratios. Upon saponification the alkaloid yields 4 moles of acetic acid, 1 mole of benzoic acid, 1 mole of a nitrogen-containing dicarboxylic acid and a polyhydroxy nucleus. The polyhydroxy compound is shown to be identical with the polyhydroxy compounds previously isolated from wilforine, wilfordine, wilforgine and wilfortrine. The dicarboxylic acid is identical with the one isolated from wilforine and wilforgine. The formula for the sum of the components of wilforzine is in agreement with the molecular formula C41H47O17N, calculated from elementary analyses on the intact alkaloid. The alkaloid therefore appears to be identical with wilforine, except that it contains one less acetyl group. This conclusion is confirmed by the fact that acetylation of wilforzine produces wilforine as judged by the X-ray diffraction patterns of their crystals. Evidence that wilforzine is not an artifact is also presented. Silicicolin, obtained from the needles of Juniperus silicicola, has been prepared by hydrogenolysis of podophyllotoxin chloride, and is identical with desoxypodophyllotoxin.