OBJECTIVES: The economic evaluation of Tegaserod was performed using data from a randomised, double-blind, placebo-controlled, parallel group, multinational, multi-centre study to assess the efficacy of treatment with Tegaserod 6mg bid and Placebo in women with IBS-C. The study consisted of a screening period, a 2-week baseline period without medication, and a 4-week placebo-controlled treatment period. METHODS: A total of 2660 patients were randomized, to receive either Tegaserod (n=2135) or Placebo (n=525). Patients' utility were obtained using the EQ-5D at baseline, 2 and 4 weeks, and used to construct a quality-adjusted life year (QALY) for each patient. The EQ-5D was completed by a subpopulation of 277 patients (235 Tegaserod: 42 Placebo). The economic perspective was that of a third party pharmacy payer, based only on the cost of Tegaserod. Other costs were not included. It was assumed that patients receiving Placebo represent untreated patients and the cost of drugs in this arm was set at zero. The gain in QALYs for each patient was calculated as the area under the utility curve from baseline to four week follow-up. RESULTS: The utility data suggests that patients in the Tegaserod group have a significantly higher, 0.074 (95% CI: 0.009 to 0.139; p=0.027), EQ-5D score at follow-up than Placebo treated patients after adjusting for baseline utility score. CONCLUSIONS: These utilities convert to an estimated QALY of 0.052 for Tegaserod patients vs. 0.048 for Placebo: difference 0.004 QALYs. At an assumed drug cost of $5.00 per day, the estimated difference in costs, over the 4-week treatment period between the Tegaserod and Placebo treated patients is $140, which leads to an ICER of $33,004/QALY which is under the recommended threshold of $50,000/QALY for the C-E of new treatments.