The present invention provides a novel acid addition salt of 1-(5-(2,4-difluorophenyl)- 1 -((3 -fluorophenyl)sulfonyl)-4-methoxy- 1 H-pyrrol-3 -yl)-N-memylmethanarnine. The above- described acid addition salt can have not only excellent proton pump inhibitory activity, gastric damage inhibitory activity and defensive factor-enhancing effect, but also excellent eradication activity against H. pylori and thus can be effectively used for the prevention and treatment of gastrointestinal injury due to gastrointestinal track ulcer, gastritis, reflux esophagitis, or H. pylori.