The inhibitory effects of isoliensinine (IL), a bisbenzylisoquinoline alkaloid extracted from the seed embryo of the traditional chinese medicinal herb Nelumbo nucifera Gaertn, on the proliferation of porcine coronary arterial smooth muscle cells (CASMCs) induced by angiotensin II(Ang II) and its mechanisms of action were investigated. Counting cultured cell number, MTT assay, immunohistochemical method and Western blot were adopted. Ang II 0.1 micromol l (-1) significantly evoked CASMC proliferation by 42%, which could be dose-dependently inhibited by IL 0.01-3 micromol l (-1) and the percentage of inhibition of IL 0.1 micromol l (-1) was 25%. Irbesartan (Irb) 0.1 micromol l (-1) inhibited CASMC proliferation by 22%. IL or Irb 0.1 micromol l (-1) decreased Ang II-induced overexpression of Platelet-derived growth factor (PDGF)-beta and basic fibroblast growth factor (bFGF), respectively. Both of them also declined c-fos, c-myc and hsp70 overexpression, respectively. At the same concentration, the inhibitory effects of IL on PDGF-beta were even stronger than those of Irb (P < 0.05). In summary, the data showed that IL possesses an anti-proliferative effect, which is related to the decrease of the overexpression of growth factors PDGF-beta, bFGF, proto-oncogene c-fos, c-myc and hsp70.