The disclosure concerns an extract of Acanthopanax koreanum and its use. More particularly, it concerns the extract of Acanthopanax koreanum comprising 1) the extract of Acanthopanax koreanum extracted from water, 2) among the water extract, the extract of Acanthopanax koreanum only containing ethanol insoluble part obtained by precipitating ethanol, 3) among the ethanol insoluble part, the extract of Acanthopanax koreanum containing polysaccaride with a molecular weight larger than range of 12,000˜14,000, or 4) among the ethanol insoluble part, the extract of Acanthopanax koreanum containing polysaccaride with a molecular weight larger than 100,000, which is respectively obtained from the root or stem of Acanthopanax koreanum. The extract of the present invention shows a high inhibitory activity against hepatitis and protects the liver, and thus, can be used for the treatment or prevention of hepatitis, or as a liver protective drug.