The purpose of this research was to investigate effects of Bambusae Caulis in Liquamen(BCL) on T-lymphocytes and peritoneal macrophages in mice. The apoptosis and subpopulation of T-lymphocytes were tested using a flow cytometer. The phagocytic activity of mouse peritoneal macrophage was tested using a luminometer. Nitric oxide production was tested using a Griess reagents. BCL induced T-lymphocytes apoptosis. BCL increased $T_H$ cells population and decreased $T_C$ cells population of T-lymphocyte, but did not affect splenocytes subpopulation. BCL increased nitric oxide production and phagocytic activity of peritoneal macrophage in mice. These results suggest that BCL regulates the immune system in consequence of an increase in helper T cell population and macrophages activation.