Quality of Life (IBS-QOL) measure are limited. The objective of this study was to evaluate the changes from baseline of the IBS-QOL scores, symptom scores and health economic data in IBS patients, after 4 and 8?weeks of treatment with mebeverine hydrochloride or pinaverium bromide. Methods This was a prospective observational cohort study in patients with IBS, diagnosed using the Rome?III criteria in four countries (Poland, Egypt, Mexico and China). Results A total of 607 patients were enrolled. At baseline, the IBS-QOL total scores were 52.0 in Poland, 48.9 in Egypt, 51.9 in Mexico, 76.4 in China and 56.4 overall. Increases in IBS-QOL total score were statistically significant at Weeks?4 and 8 overall and in each country (overall: 11.8 at Week?4, 24.3 at Week?8; p? Conclusions This study demonstrated that IBS patients have a substantially reduced HR-QoL and that treatment with mebeverine hydrochloride or pinaverium bromide improved HR-QoL." />