OBJECTIVES: Irritable bowel syndrome (IBS) is a chronic and symptomatic gastrointestinal disorder characterized by abdominal pain/discomfort, bloating and altered bowel habit.Tegaserod, a 5-HT4 receptor antagonist, is effective, safe, and well tolerated in the treatment of patients with irritable bowel syndrome (IBS) with constipation. Due to increasing pressure on healthcare budgets, it has become important to investigate not only the clinical safety and efficacy of new treatments, but also their cost-effectiveness (C/E). The aim of this study was to assess, from a payor perspective, whether tegaserod would be C/E in the treatment of IBS patients, excluding those with IBS with diarrhea. METHODS: Female and male subjects were randomized to receive tegaserod 6 mg b.i.d or placebo for 12 weeks. Patients (247 tegaserod; 238 placebo) filled out the EuroQol (EQ-5D) at baseline, Week 4, and Week 12. A 12-week economic study was undertaken to assess the incremental cost-effectiveness (ICER) of tegaserod. Costs and benefits were bootstrapped to obtain 95% confidence intervals of the ICER. C/E acceptability curves were calculated using a range of daily costs of tegaserod, and the probability of treatment being C/E was assessed at threshold willingness to pay of 50,000€ per quality-adjusted life-year (QALY). RESULTS: The utility gained between tegaserod and placebo calculated as the difference between the areas under the curve was 0.0077 over 12 weeks in favor of tegaserod. Assuming a daily tegaserod cost of 2€, 3€, 4€, and 0€ for placebo, the median ICER of tegaserod ranged between 19,000€ and 38,000€ per QALY gained, with the probability of being C/E at threshold of 50,000€ per QALY ranging from 90% to 69%. CONCLUSIONS: This study established from a randomized controlled clinical trial that tegaserod is C/E in the treatment of patients with non-diarrhea IBS.