The oleanane triterpenoid CDDO-imidazole (CDDO-Im) is reported to activate Nrf2/ARE signaling by breaking the interactions between Keap1 and Nrf2 in the cytosol and confer protective effects such as the inhibition of pulmonary hemorrhage, proteinaceous edema, and inflammatory cell infiltration on hyperoxia-induced ARDS. This evidence concerns the gene NFE2L2 and acute respiratory distress syndrome.