Wikstromia elliptica Merrill (Thymelaeaceae) represents a genus of some 70 species that is indigenous to parts of Southeast Asia, Australia, and the Pacific (2). This species was selected for study as part of a continuing search for tumor inhibitors from plants when a CHCl3 extract of the combined stem wood and stem bark displayed significant activity against the P-388 lymphocytic leukemia test system in cell culture, when assessed using standard protocols (3). Bioactivity-directed fractionation of this extract has led to the isolation of five cytotoxic substances, namely, the lignans, (±)-5' methoxylariciresinol (a new compound, 1), (±)-lariciresinol (2), and (±)-syringaresinol, as well as the coumarins, daphnoretin and umbelliferone. No previous phytochemical or biological studies appear to have been performed on extracts of W. elliptica.