A review.General approach in proteome anal. by 2D electrophoresis was first described.The recent findings on gene expression profiles of hepatic stellate cells of the activated status were summarized.The difference in expression profiles between in vitro and in vivo activation, function of newly identified protein such as STAP, and the relationship of stellate cell activation to reconstitution of extracellular matrix proteins were discussed.The potential application of the findings obtained by the proteome analyses to the screening of drugs for liver fibrosis was also discussed.