Paeoniflorin is the main active ingredient of Chinese herbaceous peony. This study is to investigate the protective effect of paeoniflorin (Pae) on acute brain damage induced by lipopolysaccharide (LPS) in mice. The mice were randomly assigned to the normal control, model control (LPS), as well as groups of paeoniflorin and lipopolysaccharide (Pae + LPS). Then the mice were administered intraperitioneally with normal saline or Pae (10, 30 mg · kg(-1)) once daily for 6 d. One hour after intrapertioneally treatment on the seventh day, each group were injected LPS (5 mg · kg(-1)) to establish the endotoxin lipopolysaccharide inflammation model except the normal group. The mice were sacrificed after 6 h and the brain homogenates were prepared and measured. The malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), hydrogen peroxide (H2O2), succinatedehydrogenase (SDH), Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase were dectected by the colorimetric method. The levels of HO-1 and Nrf2 protein in subcellular fractions of brain tissue were detected by Western blot. The results demonstrated that the administration with paeoniflorin reduced the levels of the MDA production; significantly increase the activities of antioxidant enzyme (SOD and GSH-PX). In addition, paeoniflorin could enhance the total antioxidant capacity, decrease the level of H2O2, and increase the activities of SDH, Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase. Furthermore, paeoniflorin can increase the expression of HO-1 and activate the nuclear transfer of Nrf2. Taking together, these findings suggest that paeoniflorin alleviate the acute inflammation in mice brain damage induced by LPS, which is related with its antioxidant effect and improvement of energy metabolism.