A 49-year-old man, diagnosed as having liver cirrhosis previously, was admitted to a hospital due to accumulation of ascites. Though the decrease of liver function was not severe, laboratory studies disclosed marked hypoproteinemia with a level of TP: 5.0 g/dl and Alb: 2.2 g/dl. Radiological and endoscopic examinations of stomach revealed multiple polyps from the body to antrum, and dropping of mucus from these lesions was observed. Histological investigation of polypectomied specimen revealed hyperplasia of surface epithelium and infiltration by inflammatory cell infiltration. Then, the patient was transferred to our hospital for further examination. We measured fecal α1-antitrypsin clearance and confirmed the protein-losing process in the gastrointestinal tract. Morphological examination of small intestine and colon did not show any abnormal features. All of these results suggested the gastric polyposis with protein-losing gastropathy. The measurement of fibrinolytic activity of the gastric mucosa showed high concentration of f ibrinolytic activity. Initially, antif ibrinolytic therapy with oral tranexamic acid had been performed, but it was ineffective. Therefore, cimetidine and irsogladine maleate were administered.About 3 months later, ascites and hypoproteinemia improved gradually while the gastric polyposis remained unchanged. It was reported that cimetidine has an inhibitory effect on protein-losing in the gastric mucosa by tightening the tight junction of gastric epithelium. In addition, it was reported that irsogladine maleate has the action of reinforcing and stabilizing intercellular binding in the gastric epithelium. Cimetidine and irsogradine maleate are positively available for the treatment of protein-losing gastropathy should be administed because of their stabilizing effect of the gastric epithelium.