Our in vivo study showed Arm exerted inhibitory effects on hepatic fibrosis in BDL rats, including (a) reduction of hepatic fibrosis scores and collagen contents of livers in BDL rats, (b) attenuation of hepatic injury in terms of plasma ALT and AST levels, (c) reduction of hepatic mRNA expression levels of procollagen I (col 1α2), transforming growth factor-β1 (TGF-β1), tissue inhibitor of metalloproteinase-1 (TIMP-1), intercellular adhesion molecule-I (ICAM-1), iNOS, and interleukin (IL)-6 genes, and (d) improvement of hepatic mRNA expression level of metallothionein gene. The gene discussed is NOS2; the disease is Hepatic fibrosis.