IgA nephropathy (IgAN) is the most common primaryglomerulonephritis worldwide, yet there is no effective or specific therapy. Shen San Fang (S3F) is a traditional Chinese herbal medicinal formula that has been used in China for many/years to treat patients with hematuria. The aim of this study is to test the therapeutic: value of S3F in an experimental model of IgAN. IgAN was induced in Lewis rats by continuous oral immunization with bovine gamma-globulin (BGG) in the drinking water for 8 weeks, followed by intravenous injection of 1 mg BGG daily for 3 successive days. The rats were randomly divided into four groups (five rats/group): control, control receiving S3F, induction of IgAN, and IgAN receiving S3F. S3F decoction was fed to rats beginning week 4 from the first day of oral sensitization with BGG. The S3F treatment was continued until the rats were sacrificed or for a 4-week period. Hematuria, renal immun6histochemistry for IgA and transforming growth factor-beta 1 (TGF-beta 1), renal histopathology, and renal content of TGF-beta 1 were measured. Rats developing IgAN had marked hematuria, profound mesangial proliferation and mesangial expansion, intense and diffuse glomerular IgA deposition, increased glomerular TGF-beta 1 expression, and raised renal TGF-beta 1 levels. S3F treatment resulted in a significant reduction of hematuria, decreased mesangial IgA deposition, weaker immunostaining of TGF-beta 1 in glomerulus, and a lower renal TGF-beta 1 concentration. Our animal data suggests a therapeutic value for the Chinese medicinal formula S3F in experimental IgAN. This beneficial effect was due to reduced glomerular IgA deposition and TGF-beta 1 expression. Our preliminary findings hold promise for future human therapy.