Many natural products have been used as immunomodulators either as immunosuppressants or immunostimulators. Recently, our lab has successfully isolated a 1,6-di-O-caffeoyl-β-d-glucopyranoside, monomer named Caffeoyl Glycoside (CG) from the roots of Picrorhiza scrophulariiflora (Kutki). In the present study, we evaluated the effects of this compound on immunomodulation in vitro. Our results showed that CG stimulated cell proliferation of splenocytes and peritoneal macrophages, and enhanced the cytotoxicity of natural killer (NK) cells significantly. CG also increased CD4 and CD8 cell populations. Moreover, we found that CG has immunomodulatory activity by regulating expression of Th1 and Th2 related cytokines. Taken together, these results indicated that CG might have potential effects in regulating the immune system, and this compound might be a useful immunotherapeutic agent in treating various immunity-related diseases.