Objective : Phyllostachyos Folium (PF) has been used to treat patients with febrile disease consuming the body fluids marked by fever with restlessness, thirst etc. In the theory of herbology, PF can clear away heat and promote the production of the body fluids, relieve restlessness. Recently PF is known to have anti-bacterial, anti-oxidantic effects. Methods : The present study was carried out to investigate the effects of PF on solid tumor in mice in terms of immune-potentiating and direct cytotoxic action of PF in vitro and vivo study. The present author investigated thymocyte and splenocyte proliferation to confirm immune-potentiating activity of PF and also investigated tumor/body weight ratio and survival rates in tumor bearing mice. Result : In this study, administration of PF decreased tumor/body weight ratio significantly, and prolonged survival duration compared to non-treated control. In addition, treatment with PF suppressed proliferation rate of Sarcoma 180 (S-180) cells significantly, and elevated proliferation rates of thymocytes isolated from normal mice. These results were co-related with in vivo study. Conclusion : In conclusion, these results suggest that PF is useful to treat patient with solid tumor, because PF has direct toxic action for tumor cell and immune -potentiating action for T cells. Further study will need to elucidate exact mechanisms related in anti-cancer action of PF.