The purpose of the present invention is to provide: a composition for inhibiting myofibrosis, which contains, as an active ingredient, a component that can be safely ingested over a prolonged period of time； and a method for safely inhibiting myofibrosis. The present invention provides a composition for inhibiting myofibrosis, which contains quercetin or a glycoside thereof as an active ingredient.本發明以提供一種含有以可長期安全地攝取的成分為有效成分之抑制肌纖維變性用組成物，以及一種安全地抑制肌纖維變性之方法為目的。本發明提供一種含有槲皮素或其配糖體作為有效成分之抑制肌纖維變性用組成物。
