Bronchial asthma is a chronic inflammatory disorder of the airway accompanied by increased vascular permeability. Vascular endothelial growth factor (VEGF) is a potent stimulator of bronchial inflammation, airway remodeling, and physiologic dysre-gulation that augments antigen sensitization and T-helper type 2 cell (Th2)-mediated inflammation in allergic airway diseases. The p38 mitogen-activated protein kinase (MAPK) appears to play an important role in various pathophysiological responses and has been suggested to be involved in many processes considered critical to the inflammatory response and tissue remodeling. However, there are little data on the relationship between p38 MAPK signaling and VEGF expression in allergic airway disease. Using ovalbumin (OVA)-inhaled mice and a selective p38 MAPK inhibitor, SB 239063, the involvement of p38 MAPK in aller-gen-induced VEGF expression in the airway was evaluated. The increases of phosphorylation of p38 MAPK, VEGF protein expression, and vascular permeability in the lung after OVA inhalation were decreased substantially by the administration of SB 239063. In addition, SB 239063 significantly reduced the increase of Th2 cytokines and OVA-specific IgE. The inhibition of p38 MAPK or VEGF signaling prevented and also decreased the increases in the number of inflammatory cells and airway hyperresponsiveness in OVA-induced allergic airway disease. These results indicate that inhibition of p38 MAPK may attenuate allergen-induced airway inflammation and vascular leakage through modulation of VEGF expression in mice.