Objective To afford the basis for the application of Sinomenine(SIN) in the proposal for organ transplantation, the expression of TGF-? 1 was explored in inborn WistarSK kidney transplantation model. Methods Forty-eight recipients were divided into 4 groups at random:group 1 being used as control and treated with 0 9% natrii chloride(3ml?kg -1 ?d -1 ,ip), group 2 treated with SIN(30mg?kg -1 ?d -1 ,ip),group 3 treated with CsA(2 5mg?kg -1 ?d -1 ,ip),group 4 treated with SIN(30mg?kg -1 ?d -1 ,ip) combined with CsA(2 5mg?kg -1 ?d -1 ,ip).Allografts of 6 recipients from each group were harvested at day 6 before end stage rejection for histological studies. The synergistic effects of SIN combined with CsA were assessed by COX proportional hazards model. The quantitative methods of immunohistochemistry were used for analysis on expression of TGF-? 1.Results Control recipients rejected their allografs at day 9 post-operation, the average life time was 7 83?9 75 days. Treated with either SIN(30mg?kg -1 ?d -1 ,ip) or subtherapeutic doses of CsA(2 5mg?kg -1 ?d -1 ,ip) allografts survival was mininally prolonged. Combined treatment with SIN and subtherapeutic doses of CsA led to a significant prolongation of graft survival(group 4), more than 18 days. The expression of TGF-? 1 was enhanced significantly in group 2 and group 3.No synergistic effect of SIN combined with CsA on expression of TGF-? 1 was observed. Conclusion The therapeutic value of SIN in rat kidney allograft model suggests that this safe chinese medicine has remarkable efficacy of anti-acute rejection in rat kidney transplantation. It shows significant synergistic effect with sub-therapeutic CsA. The immunosuppressive efficacy of SIN is probably based on enhancing express of TGF-? 1. No synergistic effect of SIN and CsA on expression of TGF-? 1 indicates low danger of fibrosis of allografts. SIN will be a hopeful chinese medicine for immunosuppressive treatment in organ transplantation.