Aim To study the effects of Free Anthra-quinone from Rhubarb (FAR)on myocardial CTGF and collagen expression and interstitial fibrosis in dia-betic rats.Methods The male SD rats were randomly divided into normal group (CON),diabetic cardiomy-opathy group (DCM) and FAR treatment group (FAR).Streptozocin was intraperitoneally injected in-to the animals in the latter 2 groups to induce diabetic rat model.The model was expected to be stable for 2 weeks before the treatment.At the end of the 8th week in treatment,fasting plasma glucose and heart mass in-dex were measured.Masson staining was used to ob-serve the myocardial fibrosis.RT-PCR was used to de-tect the mRNA levels of CTGF,procollagen type Ⅰand collagen type Ⅲ.Immunohistochemical method was used to detect the content of CTGF.ELISA was used to detect the depositions of collagen type I and collagen type Ⅲ. Results Compared with CON group,fasting plasma glucose,heart mass index,the degree of myocardial fibrosis,and the expressions of CTGF,collagen type I and collagen type Ⅲ in left ven-tricular myocardial tissue of DCM group were signifi-cantly increased. However, compared with DCM group,fasting plasma glucose,heart mass index,the degree of myocardial fibrosis,and the expressions of CTGF,collagen type I and collagen type Ⅲ in left ven-tricular myocardial tissue of FAR-treated rats were sig-nificantly decreased.Conclusion FAR retards the process of myocardial fibrosis in diabetic rats by down-regulating the expression of CTGF,reducing the syn-thesis and depositions of collagen type I and collagen type Ⅲ.