Effects of the extract of oriental herbal composition, Jang Baek Union (JBU), on hangover and liver function were studied in rats. To investigate anti-hangover effect, alcohol concentration and acetaldehyde concentration of blood were measured after oral ethanol treatment. Blood alcohol concentration was significantly reduced by pre-treatment of JBU extract. The effect of JBU extract on the blood acetaldehyde concentration was more significant than commercial product used as a positive control. To investigate hepato-protective effect, serum GOT and GPT levels and histological changes of liver tissue were analyzed in $CCl_4$-treated rats. JBU extract adminstration significantly inhibited the increase of serum GPT and GOT levels induced by $CCl_4$-treatment. Moreover, histological injuries of liver tissue such as fatty changes and sinusoidal leukocytosis were inhibited by JBU extract.