Although directly active as an antimicrobial (Suay et al. 2000), according to most studies reishi mushrooms do not act directly as an tumoricidal against cancers as do many other mushroom species (Ooi et al. 2002). Reishi primarily functions as a biological response modifier, stimulating production of macrophages (often a consequence of the effects of interleukins-1, -2, -6, -10), activating the host's production of natural killer cells, T cells, and tumor-necrosis factors. More than 100 distinct polysaccharides and 119 triterpenoids from this species have been isolated, from both the mycelia and fruitbodies (Zhou and Gao 2002). Of those that have been identified thus far, many triterpenoids and polysaccharides demonstrate immunomodulatory properties.