Disclosed is a novel technique which enables to increase the anti-fungal, anti-viral or anti-bacterial activity of an alkyl gallate and enables to cause the alkyl gallate to be dissolved in water. Specifically disclosed is a pharmaceutical alkyl gallate composition which comprises: (A) an alkyl gallate which has an alkyl group having 5 to 16 carbon atoms; and (B) an alkyl gallate having an alkyl group in which the number of carbon atoms in the alkyl group is smaller than that of the alkyl gallate (A). Preferably, the number of carbon atoms in the alkyl group of the alkyl gallate (B) is 2 to 7. The composition may further comprise (C) at least one member selected from an alkali metal salt, boric acid, sodium borate and an organic salt.