OBJECTIVES: To evaluate the impact of tegaserod 6mg b.i.d. on the quality of life (QoL) of men and women with IBS-C, as defined by Rome II criteria. METHODS: A multicenter, open-label, prospective, single-cohort study was conducted in Spain. Patients entered a one-month, treatment-free, baseline period followed by three-months' treatment with tegaserod 6mg b.i.d. and subsequently, a one-month withdrawal period (no treatment). QoL was assessed at the end of baseline, treatment and withdrawal periods using the IBS-QOL; a validated modified disease-specific instrument and the SF-36; a validated generic instrument. Patients recorded their level of IBS symptom relief in a weekly diary. Patients were considered responders (R) if =two-weeks' satisfactory relief of global IBS-C symptoms was experienced during the last month of treatment. RESULTS: Of 167 patients (20 men, 147 women; mean age 43.5 years) included in the analysis, 72% responded to tegaserod. At baseline, SF-36 scores from IBS-C patients were lower than those from the general population, but increased in all dimensions with treatment (p=0.0068 for General Health), reaching values similar to those of the general population. An increase in all SF-36 dimensions was observed in responders (R), whereas a decrease occurred in non-responders (NR, General Health dimension p=0.004). IBS-QOL scores (from baseline to treatment) significantly increased in all dimensions (p<0.0001 for overall assessment). The mean increment in IBS-QOL was greater for R than NR (Overall dimension, p<0.05). Upon treatment withdrawal, some dimensions of SF-36 and IBS-QOL scores decreased but did not return to pretreatment levels. CONCLUSIONS: QoL is impaired in IBS-C patients. Treatment with tegaserod 6mg b.i.d. improves QoL in patients with IBS-C to a level almost equivalent to that of the general population, and deterioration in QoL occurs upon treatment discontinuation.