Antrodia cinnamomea is an edible fungus endemic to Taiwan that has been attributed with health promotion benefits. An A. cinnamomea mycelium health food product, which was produced by solid-state culture, was selected as the target for investigation in this study. Fourteen representative metabolites of A. cinnamomea mycelium (EMAC) were selected as index compounds to establish the metabolite profile for evaluation of EMAC product quality. It was also demonstrated that EMAC administration significantly reduced liver inflammation and serum oxidative stress in vivo. 4-Acetylantroquinonol B obtained by a bioactivity-guided fractionation from EMAC was able to not only inhibit LPS-induced nitric oxide formation in macrophages but also protect against ethanol-induced oxidative stress in liver cells. The results suggest this A. cinnamomea product might be a potent antioxidative and anti-inflammatory supplement for chemoprevention.