bstract Cancer has been the first lethal factor in Taiwan, and hepatitis B is also a serious problem in our country. We have identified that the extracts of Taiwanese Schisandraceous plants, including Schizandra arisanensis, Kadsura matsudai and K. japonica, have inhibitory effect on type B hepatitis surface antigen (HBsAg) and e-antigen (HBeAg). Besides, we also find that the extracts of Echinops grijsii can inhibit the growth of human cancer cell line, KB and Hela. To purify active compounds by using column chromatography and high-performance liquid chromatography, we have furnished fifty-eight compounds from above Schisandraceous plants, including thirty-seven C18 lignans composed of [6.8.6]-dibenzocyclooctadiene skeleton, nine C19 homolignans, four triterpenes, three steroids and five cyclic-aromatic compounds. In the case of Echinops grijsii, we got thirteen major compounds containing eight thiophenes, four triterpenes, and a sterol. Structural elucidation of the novel homolignan and ten lignans are based on the spectral and chemical analyses, mainly by using two-dimensional nuclear magnetic resonance (NMR) of 1H and 13C nucleus. From the anti-HBsAg and anti-HBeAg assay, we found that four of new C18 lignans and one known (+)-gomisin K3 (33) lignan exhibited the significant inhibitory effects on surface antigen of hepatitis B virus. Moreover, to modify the known lignans, kadsurarin with different halogens and functional group having nitrogen atom, as well as (+)-gomisin K3 with several kinds of phenyl compounds and sulfur functional groups are processed. The preliminary structures and bioactivity relationships (SAR) studies demonstrated that (+)-gomisin K3 with sulfuric functional group could decrease cytotoxicity and increase inhibitory effect on surface antigen and e-antigen of hepatitis B virus. In the part of studying synthesis by using inactive 5¡¦-(but-3-en-1-ynyl)-2,2¡¦ -bithiophene (1) from Echinops grijsii, the yne-ene moiety of its structure was hydrolyzed into carbonyl group and then was attached a serious of various carbon number of hydroxy groups. Besides the above experiment, £\-trithienyl (1) was served as a substrate and made it into unsaturated carbonyl group, which then was linked with a series of hydroxy groups. Cytotoxicity datum showed that the derivatives of bi-thiophene have better anticancer activity than derivatives of tri-thiophene. And the assay results also exhibited that the bi-thiophene derivatives with hydroxy group with less than three carbon numbers have better inhibitory activity against cancer cells.