The purpose of this study is to investigate the effect of water extract from Artemisiae Argi Folium Fermented with Lactobacillus pentosus (AFL) on hydrogen peroxide production within human hepatocyte HepG2 cells treated with gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde. AFL (0~400 ug/mL) was treated with gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde. And the intracellular productions of hydrogen peroxide were measured by dihydrorhodamine 123 (DHR) assay. AFL showed the restoration of the intracellular productions of hydrogen peroxide which were reduced by gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde in HepG2 Cells. AFL could be supposed to have the hepatoprotective effect related with hepatocytologic signaling activity against gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde.