Background: The fruits of Schisandra chinensis have been used traditionally as the medicinal materials in East Asia. Their extracts have been reported to be cytotoxic to several cancer cells and phytochemical research has identified numerous cytotoxic lignans. Objectives: We reviewed for the effects of cytotoxic lignans against various human cancer cells. Materials and Methods: Solvent extraction of fruits in aqueous methanol and fractionation of the extract into H2O, n-BuOH, and EtOAc fractions (Fr) were carried out. Column chromatography (CC) of the non-polar EtOAc Fr, which indicated cytotoxicity to cancer cells, was performed to isolate the cytotoxic lignin. They were identified on the basis of the intensive spectroscopic interpretation of IR, 1D-, 2D-NMR, and mass spectrometry data. The cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and cell staining using Hoechst 32258 and propidium iodide. Results: Anwulignan was isolated and identified as a cytotoxic principal component. The IC50 value was calculated to be 22.01 ± 1.87, 156.04 ± 6.71, and 32.68 ± 2.21 μM for human stomach adenocarcinoma, human colon cancer (HT29), and human cervical cancer cells, respectively. Conclusion: Solvent extraction, systematic fractionation, and repeated CC for S. chinensis fruits led to the isolation of a lignin identified to be anwulignan based on various spectroscopic analyses. Anwulignan demonstrated very high cytotoxicity to most human cancer cell lines, and cell death was induced by apoptosis.