The present invention relates to a transglutaminase inhibitor comprising chlorogenic acid, a pharmaceutically acceptable salt thereof, or a derivative thereof. More particularly, the present invention relates to a transglutaminase inhibitor comprising chlorogenic acid, a pharmaceutically acceptable salt thereof, or a derivative thereof which effectively inhibits the activity of transglutaminase, the overexpression of which is responsible for the etiology of various diseases, and to novel uses thereof. The present invention provides a transglutaminase inhibitor and a method of inhibiting transglutaminase, both of which are based on using chlorogenic acid, a pharmaceutically acceptable salt thereof, or a derivative thereof as an active ingredient. Featuring the use of chlorogenic acid, a pharmaceutically acceptable salt thereof, or a derivative thereof, the novel method of inhibiting transglutaminase according to the present invention is safely applied to patients who suffer from the diseases caused by the overexpression of transglutaminase, thereby obtaining an inhibitory effect against transglutaminase without causing side-effects.
