C57Bl mice, unlike LACG or BALB mice, show a significant preference for 12% (w/v) ethanol solution compared to water. C57Bl mice which have been rendered tolerant to but not dependent upon ethanol by a programme of enforced ethanol drinking lose this preference on withdrawal of compulsory ethanol. Loss of preference also occurs following one or more acute injections of ethanol ( 4ml /kg) and persists in mice 12 weeks following withdrawal. It is suggested that this long-lasting loss of preference has a CNS basis and is not due merely to taste aversion.