Hepatic diseases can be prevented or treated by administering an isoprenylamine derivative represented by the general formula (II) ##STR1## [wherein n represents an integer of 4-12, m represents an integer of 0-3, Ar represents a phenyl group, a furyl group, a thienyl group or a pyridyl group, said group being optionally substituted with one or more of an alkyl group of 1-4 carbon atoms, and alkoxy group of 1-4 carbon atoms, a methylenedioxy group, a hydroxy group or a halogen atom, and R represents a hydrogen atom or an alkyl group of 1-4 carbon atoms] or a pharmacologically acceptable salt thereof at a daily dose of 0.01-500 .mu.g/kg.A lipid emulsion of the compound (II) is particularly useful and can be administered at a remarkably lowered dose as compared with other pharmaceutical preparations.