The lack of validated outcome measures is a key limitation for the evaluation of drug efficacy in the treatment of irritable bowel syndrome (IBS). In clinical trials with tegaserod, the Subject's Global Assessment (SGA) of Relief (a global measure that includes overall wellbeing, abdominal pain/discomfort, and bowel function) was used to identify responders. A total of 1680 patients with IBS with constipation were included in two clinical studies comparing tegaserod with placebo. The SGA of Relief was obtained weekly by a single, self-administered question with five possible answers. Responders for the SGA of Relief reported statistically significant (P<.001) and clinically relevant improvements in multiple IBS-related symptoms compared with nonresponders. Response was also associated with a significant improvement in quality of life. The SGA of Relief is reliable as a new outcome measure for assessing response to therapy in IBS patients and has demonstrated responsiveness and reproducibility.