ONO-3951 Phase II Study

INTERVENTION: Intervention name : ONO‐3951 INN of the intervention : Asimadoline Dosage And administration of the intervention : Oral administration Control intervention name : Placebo Dosage And administration of the control intervention : Oral administration CONDITION: Irritable bowel syndrome with diarrhea(IBS‐D) PRIMARY OUTCOME: Percentage of subjects with improvement in abdominal pain SECONDARY OUTCOME: Percentage of subjects with improvement in stool frequency, etc. INCLUSION CRITERIA: 1. Subjects diagnosed with IBS‐D based on the Rome III diagnostic criteria