The present invention provides a composition containing a benzamidine
derivative that does not decompose even when placed under humidification
conditions and a method for stabilizing a benzamidine derivative.
According to the present invention, decomposition reaction of a
benzamidine derivative can be suppressed by adding to a benzamidine
derivative represented by general formula (I) or a pharmacologically
acceptable salt thereof, at least one type of electrolyte selected from
the group consisting of halide salts of alkaline metal or alkaline earth
metal and alkaline metal salts or alkaline earth metal salts of
perchloric acid. ##STR00001##