To investigate the effects of Biejia Ruangan Tablet (acurrency signiae-(1)e(3)-c"(2)e1/2-e,ec parts per thousand double dagger ae-(1), BRT)-containing serum on the expression of matrix metalloproteinase (MMP-9) and tissue inhibitor of metalloproteinase (TIMP-1) in cultured renal interstitial fibroblasts. Different BRT-containing sera were prepared by gastric gavages to rats with the high-dose (7 g/kg), mid-dose (3.5 g/kg), and low-dose (1.75 g/kg) BRT respectively. The expression of extracellular matrix in NRK-49F cells was induced by treatment with human transforming growth factor-beta 1 (recombined human TGF-beta 1), and BRT-containing serum. Western blotting and Northern blotting were used to measure type I and III procollagen, MMP-9, and TIMP-1. The high dose BRT-containing serum could decrease the type I and III procollagen gene expression which boosted by TGF-beta 1, at the same time cut down TIMP-1 protein and gene expression which increased by TGF-beta 1 (P < 0.05). Treatment of cells with recombined human TGF-beta 1 had no significant effect on MMP-9 expression and BRT-containing serum also had no effect on MMP-9 expression. High dose BRT has anti-fibrosis effects in NRK-49F cells, as indicated by its inhibition of type I and III procollagen and TIMP-1 expression.