Efficacy and Safety of DT01 Tablets in Patients With Irritable Bowel Syndrome With Diarrhea

Inclusion Criteria: * Patients aged 18 years or older. * Has a diagnosis of IBS-D (Irritable Bowel Syndrome with Diarrhea) and meets the Rome IV Criteria * Additional criterion: more than 3 bowel movements per day at least 25% of the time in the last 3 months. * For patients older than 50 years OR patients with a positive family history of colorectal cancer: Normal results from colonoscopy/flexible sigmoidoscopy performed within the last 2 years. * For patients aged 65 years or older: Absence of ischaemic colitis, microscopy colitis or any other organic gastrointestinal disease as evidenced by the results of a colonoscopy/flexible sigmoidoscopy with biopsy performed within 12 months. * Mentally competent, able to give written informed consent, and compliant to undergo all visits and procedures. * Unrestricted access to a touch-tone telephone. * Willingness to refrain from using loperamide within 3 days prior to run-in visit and during the run-in period. * For women of childbearing potential: Use of a highly effective contraceptive method with a failure rate \<1% per year throughout the entire study period. Additional criteria at randomisation: During both weeks of the run-in period: 1. A weekly average of worst abdominal pain in the past 24 hours with a score of ≥ 3.0 according to the Visual Analogue Scale (VAS). 2. At least one bowel movement on each day. 3. A weekly average of at least 3 bowel movements per day. 4. At least one stool with a consistency of Type 6 or Type 7 according to the Bristol Stool Scale (BSS) on at least 2 days per week. 5. Less than 2 bowel movements with a consistency of Type 1 or Type 2 according to the BSS per week. 6. Adequate compliance with the diary recording procedure defined as at least ≥80% of the nominal daily data entry. Exclusion Criteria: * Diagnosis of IBS with a subtype of constipation, mixed IBS, or un-subtyped IBS. * History of organic GI abnormalities, inflammatory bowel diseases, complicated diverticulosis, ischaemic colitis, microscopic colitis. * History of pancreatitis, active biliary duct disease, cholecystitis or symptomatic gallbladder stone disease in the previous 6 months. * History of gluten enteropathy or lactose intolerance. * Hypersensitivity to the active substances or to any of the excipients of study drug or placebo. * History of major cardiovascular events in the previous 6 months. * History of human immunodeficiency virus infection. * Uncontrolled hypertension, insulin-dependent diabetes mellitus or abnormal thyroid function. * Evidence of clinically significant hepatic disease, severe renal insufficiency or anemia. * Use of prohibited concurrent medication within the previous month such as antibiotics, antimuscarinic drugs, drugs enhancing GI motility and analgesics. * Pregnancy or breastfeeding. * Inability to understand or collaborate throughout the study. * Participation in other clinical studies in the previous 4 weeks or concomitant enrollment in a clinical study. * Any condition that would compromise the well-being of the patient.