Acute toxicities of DWH-O1 (Ranitidine : Bismuth : Sucralfate=1.5 : 2 : 6) were investigated in Sprague-Dawley rats. Seven days after oral administration of DWH-O1 with different doses (10 g/kg, 5 g/kg, 2.5 g/kg, 1.25 g/kg, 0.625 g/kg), we examined numbers of deaths, general signs, weight measurement and histopathological examination for both sexes of rats. Summaried results are: 1) No deaths were occurred, 2) There were no pathological and clinical differences compared with control group, 3) No significant changes of body weights were observed, and 4) In histopathological examinations of organs and tissues, there was some hemorrhage in a lung tissue of low dose group for male and female respectively, but it was thought to be caused by environmental factor. The results suggest that toxicity of DWH-Ol is low and its LD_(50), is over 10 g/kg in Sprague-Dawley rats.