The present invention aims to provide a novel drug which has an excellenttherapeutic effect on biliary tract diseases and is useful for therapy and/orprophylaxisof biliary tract diseases. More particularly, the present invention provides atherapeutic or prophylactic agent for biliary tract diseases, which agentcomprises asan effective component a specific compound having a morphinan skeletonrepresented by Compound 1, or a pharmaceutically acceptable acid addition saltthereof.(see Compound 1)
