The aim of this study was to evaluate the effects of active hexose correlated compound (AHCC) intake on immune responses by investigating the number and function of circulating dendritic cells (DCs) in healthy volunteers. Twenty-one healthy volunteers were randomized to receive placebo or AHCC at 3.0 g/day for 4 wk. The number of circulating cluster of differentiation (CD)11c(+) DCs (DC1) and CD11c(-) DCs (DC2) were measured. Allogeneic mixed-leukocyte reaction (MLR) was performed. Natural killer (NK) cell activity and the proliferative response of T lymphocytes toward mitogen (phytohemagglutinin [PHA]) were measured. We also measured cytokine production stimulated by lipopolysaccharide [interleukin (IL)-2, IL-4, IL-6, IL-10, interferon gamma-gamma, tumor necrosis factor-alpha). The AHCC group (n = 10) after AHCC intake had a significantly higher number of total DCs compared to that at baseline and values from control subjects (n = 11). The number of DC1s in the AHCC group after intake was significantly higher than at baseline. DC2s in the AHCC group were significantly increased in comparison with controls. The MLR in the AHCC group was significantly increased compared to controls. No significant differences in PHA, NK cell activity, and cytokine production were found between groups. AHCC intake resulted in the increased number of DCs and function of DC1s, which have a role in specific immunity.