Objective:To study the regulation effect of water extraction from Ganoderma Lucidum (Lyess. ex Fr) karst (GL W) on human immune cells and cytokine. Methods: With the technologies of MTT and FACS, the proliferation of T lymphocyte subgroup and IL 6 production in human peripheral blood lymphocytes (PBL) were studied. Results: 1. In the absence of mitogin, GL W could induce not only the inactive lymphocyte but also the PHA activited lymphocyte to proliferate in the similar concentration. The proliferation in the later was more obvious ( P