Acute lung injury, characterized by inflammation, is a main cause of respiratory failure that affects patients worldwide. Antidesmone is one compound mainly isolated from Ajugade cumbens Thunb (Labiatae), an herb agent of Labiatae family. In this research, we investigated the anti-inflammation effect of antidesmone in vitro and in vivo. Antidesmone exerted none apparently cytotoxicity in vitro and toxic in vivo. In vitro results demonstrated that antidesmone suppressed the excess inflammatory cytokines production, including tumor necrosis factor-α, interleukin-6 and interleukin-1β in lipopolysaccharide (LPS)-exposed RAW264.7 cells. In vivo results suggested that antidesmone inhibited inflammatory cytokines in the bronchoalveolar lavage fluid and lung tissue after LPS stimulation. Moreover, antidesmone attenuated the nuclear translocation of p65. Mechanism study revealed that mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) signaling pathways play important roles in antidesmone's action. Taken together, our data uncover a relative toxic anti-inflammatory drug, antidesmone, can inhibit inflammation on stimulated macrophages and thereby prevents acute lung injury by regulating MAPK and NF-κB signaling pathways.