The invention discloses new medical application of glycyrrhiza inflata ethanol extract and licochalcone A. The inventor discovers that glycyrrhiza inflata and other medical licorice root have obvious chemical ingredient difference, furthermore systematically researches the glycyrrhiza inflata ethanol extract and the important ingredient licochalcone A therein, and discovers that the glycyrrhiza inflata ethanol extract and the licochalcone A have remarkable activity in protecting oxidized cell injury, tissue injury and acute chemical liver injury. Based on the discovery, the extract and an active compound or pharmaceutically acceptable salt, ester and a solvate, a stereoisomer, tautomer, a prodrug and a mixture thereof can be used for preparing medicaments and health products for treating/preventing oxidative injury and/or acute chemical liver injury.