Purpose: This study was performed to investigate the effects of Bojungikgi-Tang on the development of experimentally-induced endometriosis in rats. Methods: Endometriosis was induced in rats by autotransplanting uterine tissue to the peritoneum and we divided the rats into three groups: (1) sham-operated group (n=8), (2) surgically induced endometriosis and untreated control group(n=8), (3) surgically induced endometriosis and Bojungikgi-Tang treated group. Bojungikgi-Tang was orally administrated for 15 days after operation. Then we measured the body weight, the volume of endometriotic implants, the weight of uterus and ovary, and analysed the concentration of cytokines(MCP-1, TNF-${alpha}$, IL-1${eta}$, IL-6) in peritoneal fluids. Histopathology, immunohistochemistry for COX-2 and VEGF, and histochemistry for mast cell in transplanted uterine tissue were also performed. Results: 1. The volume($mm^3$) of endometriotic implants in Bojungikgi-Tang treated group(129${pm}$39) was significantly decreased(p<0.05) compared with control group(222${pm}$109). 2. The concentration(pg/$m{ell}$) of MCP-1 in peritoneal fluids in Bojungikgi-Tang treated group(1012${pm}$248) was significantly decreased(p<0.05) compared with control group(1413${pm}$346). 3. The concentration(pg/$m{ell}$ of TNF-${alpha}$ in peritoneal fluids in Bojungikgi-Tang treated group(887${pm}$196) was significantly decreased(p<0.05) compared with control group(1126${pm}$140). 4. Histopathologically, proliferation of endometriotic epithelia, infiltration of inflammatory cells and angiogenesis in transplanted uterine tissue of Bojungikgi-Tang treated group were weakly observed than those of control group. 5. The percentage of positive epithelial layers for COX-2 in Bojungikgi-Tang treated group(56${pm}$17) was significantly decreased(p<0.05) compared with control group(75${pm}$16). 6. The VEGF expression of endometriotic epithelia, neovascular endothelia and stromal cells in transplanted uterine tissue of Bojungikgi-Tang treated group were weakly observed than those of control group. Conclusion: On the basis of these results, we concluded that Bojungikgi-Tang has inhibiting effects on the development of transplanted uterine tissue. And these effects may be related with decreased production of MCP-1, TNF-${alpha}$, and decreased expression of COX-2 and VEGF infiltration by administration of Bojungikgi-Tang.