AbstractThis present study was designed to evaluate the immunomodulatory activity of Konjac glucomannan (KGM) on immunosuppressed mice induced by cyclophosphamide (CTX) treatment. The mice immunodeficiency model was established by CTX. KGM was used to modulate the activities of immunosuppressive mice. It was proved that KGM could promote the proliferation of lymphocyte, thymus, and spleen indices, and alleviate the atrophy of immune organs and weight loss. Besides, in mice serum, the levels of cytokines including TNF‐α, IgG, IL‐2, and the contents of hemolysin were also increased after treatment with KGM. Furtherly, in nonspecific immunity, KGM could enhance natural killer (NK) cell lethality and pinocytic activity of mouse peritoneal macrophages. Therefore, all of these results revealed that KGM could improve the reduced immunity of CTX‐induced mice via modulation innate immunity and adaptive immunity.