Aim in order to regulate the action of small molecular G protein (ras protein) for inhibition of smooth muscle cell (SMC) proliferation response to growth factor, basic fibroblast growth factor (bFGF).Methods Antisense oligomers, modified to prevent their own degradations, were used in a concentration of 6 pool/L introduced into the serum-free medium containing bFGF (100 mg/L) in which rat aortic SMC were cultured. By means of H-thymidine incorporation and immunocytochemistry methods, DNA synthesis and expression of proliferating cell nuclear antigen. (PCNA) in SMC were detected.Results These oligodeoxynucleotides (ODN), in a time-related manner, significantly lowered the DNA synthesis of SMC by more than 90% (compared with the control). When a same nucleotides sense ODN was used instead, showed only a little effect. lmmunocytochemistry indicated that the antisense ODN can markedly reduce expression of PCNA protein which is necessary for SMC proliferation. Conclusion Antisense G protein ODN strategies may be used to resolve clinical problems caused by growth factors initiated cell proliferation.