The object is to isolate a substance having a potent anti-allergic effect inherent in tea leaves of an Assam hybrid line. Thus, disclosed is an anti-allergic agent comprising, as an active ingredient, a catechin yielded by the isolation, i.e. epicatechin-3-O-(3-O-methyl)gallate, epicatechin-3-O-(4-O-methyl)gallate, epicatechin-3-O-(3,4-O-dimethyl)gallate, epicatechin-3-O-(3,5-O-dimethyl)gallate, epicatechin-3-O-(3,4,5-O-tromethyl)gallate, an epimer thereof or the like. Also disclosed is a food/beverage, a preparation for external application, and a cosmetic including the anti-allergic agent. An anti-allergic composition can be prepared using a compound represented by the general formula (1): ##STR00001## in which R.sub.1, R.sub.2 and R.sub.3 independently represent a hydrogen atom or a methyl group.