This review deals briefly with the various medicinal components(mainly saikosaponins), their biological activities and the variation of their contents by different cultivation environment and plant parts in Bupleurum species. Bupleuri radix, a crude drug, is the root of Bupleurum falcatum L. (Korea, Japan), B. chinense(China), and their related species (Umbelliferae). There are over 120 species in Bupleurum genus throughout world, mainly Asian area, and over 5 species in Korea, investigated up to now. These plants contain many physiological active compounds and the principal components are saikosaponins. Major activities of this crude drug and saikosaponins are the anti-inflammatory and antihepatotoxic activities. Saikosaponins and their derivatives in Bupleurum spp. have been chemically studied, isolated and identified over 70 compounds in over 50 species. Other components, physiologically active ones, also have been investigated, which are the groups of lignan, flavonoid, essential oil, polyacetylene, polysaccharide, etc. Saikosaponins belong to the group of triterpenoid saponin chemotaxonomically and occur the accumulation and turnover in plant tissues through secondary metabolism, mevalonic acid pathway. The contents and kinds of saikosaponins and other components in Bupleurum spp. plants are various due to different species and growing environments, as the plant growth characters and yield are various. Most of medicinal plants as well as Bupleurum species are very useful as agricultural products and traditional medicines, and also are very valuable as genetic resources and natural products. So we need to collect, evaluate, preserve, and utilize various medicinal plants, and also to under-stand secondary metabolism and improve the breeding and cultivation techniques for the safe production of crude drugs with high quality and yielding.