The present invention relates to a composition as a transforming growth factor (TGF)-β suppressor which comprises an effective amount of guanidine compound or a pharmaceutically acceptable salt. More particularly, the present invention relates to a composition comprising a guanidine compound or a pharmaceutically acceptable salt thereof as a TGF-β suppressor, wherein the composition is characterized by suppression or reduction of TGF-β activity which is a cause of disease. The present invention relates to a method of treating various TGF-β associated diseases, the method comprising administering to the subject a composition comprising a guanidine compound or a pharmaceutically acceptable salt thereof as a TGF-β suppressor which can prevent or treat TGF-β associated diseases by suppressing or reducing TGF-β activity.
