Fatigue is a common complaint and affects the quality of life in modern people. Physical stress may induce activation of certain immune cells. Fermented porcine placenta (FPP) has been used to alleviate fatigue. Inflammatory cytokines are produced by physical stress and results in symptoms of fatigue. However, the role of FPP on fatigue-associated inflammatory cytokine production has not been elucidated yet. Thus, we estimated the anti-fatigue effect of FPP and its active components, leucine (Leu) and lysine (Lys) in activated RAW264.7 macrophages and forced swimming test (FST) fatigue animal model. Pretreatment with FPP, Leu, or Lys significantly inhibited the lipopolysaccharide (LPS)-induced tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 production without inducing cytotoxicity on LPS-stimulated RAW264.7 macrophages. FPP, Leu, or Lys inhibited the production of nitric oxide and downregulated the expression of inducible nitric oxide synthase on LPS-stimulated RAW264.7 macrophages. Furthermore, caspase-1 activities increased by LPS were significantly reduced by FPP, Leu, or Lys. In the FST, inflammatory cytokine levels of the mice administrated with FPP, Lys, and Leu were significantly reduced compared with the control group at 21 days. Collectively, these results show that anti-fatigue effect of FPP and its active components, Leu and Lys might be derived from the down-regulating of inflammatory mediators.