The clinical effect and optimum dose of FUT−187, a novel oral protease inhibitor, were evaluated in patients with postgastrectomy reflux esophagitis. FUT−187 was administered orally at a dose each of 100mg，200mg and 300mg/day for continuous four weeks in a double blind comparative study.

　The superior improvement of endoscopic findings and final superior over−all improvement were obtained at a dose each of 200 and 300mg/day to 100mg/day，respectively. The improvement of subjective symptoms at second week after administration，the over−all improvement of endoscopic findings and final over−all improvement were observed dose−dependently，to a significant degree.

　Adverse events were observed dose−dependently，which incidence，however，were 1.6％ in the cases of 100mg/day, 9.4％ in 200mg/day，and 16.1％ in 300mg/day，respectively. This incidence in the case of 300mg/day were significantly higher than that in 100mg/day，and diarrhea and soft feces were recognized in the case of 300mg/day. These results suggested that the optimum dose，from the view point of safety，was 200mg/day or less.

　As a conclusion，balancing the efficacy and safety，the optimum dose of FUT−187was decided as 200mg/day.