Asparagus officinalis is a vegetable that is widely consumed worldwide and has also long been used as a herbal medicine for the treatment of several diseases. Although A. officinalis is generally regarded as a supplement for the alleviation of alcohol hangover, little is known about its effects on cell metabolism. Therefore, this study was conducted to analyze the constituents of the young shoots and the leaves of asparagus and to compare their biochemical properties. The amino acid and inorganic mineral contents were found to be much higher in the leaves than the shoots. In addition, treatment of HepG2 human hepatoma cells with the leaf extract suppressed more than 70% of the intensity of hydrogen peroxide (1 mM)-stimulated DCF fluorescence, a marker of reactive oxygen species (ROS). Cellular toxicities induced by treatment with hydrogen peroxide, ethanol, or tetrachloride carbon (CCl(4)) were also significantly alleviated in response to treatment with the extracts of A. officinalis leaves and shoots. Additionally, the activities of 2 key enzymes that metabolize ethanol, alcohol dehydrogenase and aldehyde dehydrogenase, were upregulated by more than 2-fold in response to treatment with the leaf- and shoot extracts. Taken together, these results provide biochemical evidence of the method by which A. officinalis exerts its biological functions, including the alleviation of alcohol hangover and the protection of liver cells against toxic insults. Moreover, the results of this study indicate that portions of asparagus that are typically discarded, such as the leaves, have therapeutic use.