This study will evaluate the tolerability, safety and efficacy of DNK333 against diarrhea caused by Irritable Bowel Syndrome in women.

Inclusion Criteria:

Women of 18 - 65 years of age with IBS-D as defined by the Rome II criteria. The Rome II criteria is a system used for diagnosing functional gastrointestinal disorders such as irritable bowel syndrome. It involves completing of a questionnaire about gastrointestinal symptoms.

Note: Patients who are 50 years of age and older must have had a colonoscopy OR a flexible sigmoidoscopy plus a double-contrast barium enema within the past 5 years, which demonstrated no clinically significant findings.

Clinically significant findings may include but are not limited to malignant tumors, multiple (≥3) or advanced adenomas, inflammatory bowel disease, diverticulitis, ischaemic colitis, lymphocytic colitis, or collagenous colitis.

Patients must report ≥ 3 days with IBS-related abdominal pain/discomfort plus at least 3 days of 2 or more of the following events during the baseline period:

1. ≥ 3 bowel movements/day

2. Bowel urgency

3. Loose or watery stool

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   Exclusion Criteria:

   • Patients who answer "yes" to either or both of the two weekly satisfaction questions during the baseline period. The questions are: (1) Over the past week did you have satisfactory relief of your IBS-related abdominal pain/discomfort? (2) Over the last week did you have satisfactory relief of your overall IBS-D symptoms?
   • Patients with hard or lumpy stools for more than one day during the baseline period
   • Lactose intolerant patients relieved on a lactose free diet
   • Use of antidepressants (tricyclic, SSRI etc), opioid analgesic drugs or drugs specifically affecting bowel motility during the course of the trial.
   • Women of child-bearing potential who do not use an acceptable methods of contraception
   • Pregnant or nursing (lactating) women