Provided is a compound useful in the prevention and treatment of non-alcoholic steatohepatitis. A prophylactic and/or therapeutic agent for non-alcoholic steatohepatitis which contains, as the active ingredient, 2-[4-[2-(benzimidazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,4 -bis(methylthio)-6-methyl-3-pyridyl]acetamide, an acid-addition salt thereof, or a solvate of the same.