The effect of Flavonoids of Gly-cyrrhiza (FG) on ethanol-induced liver injury was studied in mice. Administration of FG to mice prior to ethanol treatment ,either once daily for four days or a single dose, the increase of malondialdehyde and the decrease of reduced glutathione were inhibited dose- dependently.Electron microscopic examination showed that the ethanol-induced damage of hepatocytes could be ameliorated by FG pretreatment. However, no protective effect was observed when FG was administrated to mice after ethanol intoxication.