of the most important components responsible for the bioactivities of L. edodes. In our previous studies, a new type of heteropolysaccharide, named L2, was obtained from the fruit body of L. edodes with an average molecular weight of 26 KDa but without triple-helix conformation [Xu et al., 2012]. In vitro, L2 increased the production of nitric oxide, tumor necrosis factor α, and interleukin 6 of RAW 264.7 cells in a wide range of pH circumstances with the involvement of toll-like receptor 2 [Xu et al., 2012]. Further studies demonstrated that L2 still exhibited immunostimulating activity by altering the spatial structure of gut microbiota and differentially affecting gene as well as protein expressions in adult mice [Xu & Zhang, 2015; Xu et al., 2015a; Xu et al., 2016]. Moreover, L2 displayed anti-aging activity by restoring the age-attenuated immune responses and partly reversing the age-related composition of gut microbiota [Xu et al., 2015b]. In order to better understand the acting mechanism of L2 and to further mine new functions of L2, NMR-based metabolomics approach was employed to investigate the urine metabolic profi les of the adult mice with L2 intervention. MATERIAL AND METHODS Animal protocols and materials The detail processes of animal experiments were described in our previous report [Xu & Zhang, 2015]. Briefl y, fourteen 8-week specifi c pathogen-free male C57BL/6 mice were divided into the normal group (n=7) and the L2-treated group (n=6), respectively. Gavage administration of L2 (40 mg/kg