Dexamethasone is an analog of adrenocortical hormones that can improve the functions of capillary endothelial cells and alveolar epithelial cells, decrease pulmonary capillary permeability, protect alveolar epithelial type II cells, promote the secretion of pulmonary surfactant, increase renal blood flow, and decrease the secretion of antidiuretic hormone. Thus, dexamethasone is a key drug in the treatment of HAPE.