To investigate the effects of Active Hexose Correlated Compound (AHCC) supplementation and the mechanism action of AHCC in patients with alcohol-induced mildly elevated liver enzyme levels, participants were randomly allocated to the placebo, 1 g AHCC, or 3 g AHCC group and took the supplement for 12 wk. Subjects visited the hospital for clinical and biochemical measurements, for examination of adverse events, to return unused supplements, and to obtain their next supplements. Biochemical tests including liver enzymes, a questionnaire survey, and anthropometric measurements were collected at baseline and every 4 wk thereafter. Adherence and adverse events were evaluated. After 12 wk of supplementation, the percentage change in alanine aminotransferase (ALT) level was significantly different between the placebo (4.02±59.07%) and both AHCC groups (1 g AHCC: 223.89±20.59%, 3 g AHCC: 224.09±30.73%) (p=0.04). Serum levels of tumor necrosis factor-α (p<0.05) and interleukin-1β (p<0.01) were significantly lower, while those of adiponectin were higher in both AHCC groups than in the placebo group (p<0.01). AHCC supplementation for 12 wk may improve the levels of liver enzymes and circulating pro-inflammatory and anti-inflammatory cytokines in patients with alcohol-induced liver enzyme elevation with mildly elevated liver enzyme levels.