PROBLEM TO BE SOLVED: To provide methods useful in treating one or more subtypes of irritable bowel syndrome (IBS), or useful in treating diarrhea.SOLUTION: The invention relates to the use of peripherally selective kappa-opiate agonists, especially N-methyl-N-[(1S)-1-phenyl-2-((3S)-3-hydroxypyrrolidin-1-yl)ethyl]-2,2-diphenylacetamide and/or a pharmaceutically acceptable salt thereof for treating a subject having diarrhea-predominant IBS (IBS-D) or IBS (IBS-A) with alternating diarrhea and constipation, or a subject having diarrhea.【課題】過敏性腸症候群（ＩＢＳ）の１または２以上のサブタイプの処置に有用な、または下痢の処置に有用な方法の提供。【解決手段】末梢選択的カッパ－オピエートアゴニスト、特にＮ－メチル－Ｎ－［（１Ｓ）－１－フェニル－２－（（３Ｓ）－３－ヒドロキシピロリジン－１－イル）エチル］－２，２－ジフェニルアセトアミドおよび／またはその薬学的に許容し得る塩の、下痢型ＩＢＳ（ＩＢＳ－Ｄ）または便秘と下痢が交互に生じるＩＢＳ（ＩＢＳ－Ａ）を有する対象、または下痢を有する対象を処置するための使用。【選択図】図３
