More than 800 species of Thymelaeaceae plants from about 50 genera are widely distributed all over the world, except in the polar regions. Plants of this family are characterized by their abundance of diterpenoids with excellent biological functions, including anti-cancer and anti-HIV activities. Among these, macrocyclic daphnane-type diterpenoids, which can eradicate latent HIV-infected cells, are attracting attention as candidate compounds for novel anti-HIV drugs. Edgeworthia chrysantha is a deciduous shrub belonging to the family Edgeworthaceae that has long been used in Japan as a raw material for Japanese paper and banknotes due to its strong bark fibers. In this study, the research group isolated five daphnane-type diterpenoids with unprecedented characteristic macrocyclic structures from Edgeworthia chrysantha, and revealed their anti-HIV activity. The results obtained in this study will deepen our knowledge of the structure-activity relationship between macrocyclic daphnane-type diterpenoids and anti-HIV activity, which should lead to the discovery of new drug seeds for the treatment of HIV infection.