A therapeutic agent for liver disease containing as an active ingredient a piperazine derivative having the formula: ##STR1## wherein, A represents a phenyl, p-benzoquinonyl or cumarinyl group which may have at least one substituent selected from the group consisting of halogen, alkyl, fluoroalkyl, formyl, alkoxycarbonyl, acyl, hydroxy, alkoxy, acyloxy, glycosyloxy, amino, alkylamino, mercapto, alkylthio and nitro; B represents a single bond or a straight chain alkylene group containing 1-4 carbon atoms which may have at least one substituent selected from the group consisting of alkyl, aryl, aralkyl, hydroxy and oxo; R represents an atom or a group selected from the group consisting of hydrogen, alkali metal, alkaline earth metal, alkyl, cycloalkyl, aralkyl and aryl; and n is 2 or 8, or its pharmaceutically acceptable salt is diclosed.