OBJECTIVE : The therapeutic potentiality of Bazhengsan on the chronic nonbacterial prostatitis was investigated. METHODS : Prostatitis was induced by subcutaneous injection of the 17-beta-estradiol (E2) and dihydrotestosterone in male rat, and treated with Bazhengsan. After 8 weeks, prostatic fluid was collected for counting lecithin corpuscle density (LCD) and the organs were removed from animals and used for measuring prostate viscera coefficient (PVC). Then, prostate histopathological changes were observed by hematoxylin-eosin (HE) staining and masson staining, and expression levels of cytokines and pro-inflammatory mediators were detected by the technologies of enzyme linked immunosorbent assay, reverse transcription polymerase chain reaction or western blot. RESULTS : Bazhengsan significantly improved inflammatory responses and reduced collagen deposition in prostate tissues relative to model group. The treatment of Bazhengsan also showed a significant decrease in levels of PVC, interleukin (IL)-6, IL-8, IL-17 and increase in the levels of LCD and secretory immunoglobulin (SIg)-A relative to model group. In addition, the mRNA expression of monocyte chemoattractant protein (MCP)-1, vascular cell adhesion molecule (VCAM)-1 and fibroblast growth factor (FGF)-2, and the protein content of very late antigen (VLA)-4, CC chemokine ligand (CCL)-2 and fibroblast growth factor receptor (FGFR)-1 in prostate tissue were significantly decreased in Bazhengsan-treated rats compared to untreated control. CONCLUSIONS : Bazhengsan can significantly suppress inflammation and hyperplasia in rats with nonbacterial prostatitis, showing great therapeutic potential to the chronic prostatitis.