<qa>  What is the purpose of this study?The purpose of this study is to evaluate the presence of microscopic inflammation previously demonstrated in patients with IBS, using pCLE. The determination of the exact areas of inflammation allows a direct biopsy in a more accurate way. This type of systematic may allow in the future to classify these patients not only symptomatically constipation, diarrhea or mixed predominant IBS but also according to their degree of inflammation. There is no Gold Standard test in these patients to assess response to treatment. The possibility of using pCLE to identify the areas of microscopic inflammation allows that the degree of inflammation can be used as a monitoring parameter. Probably the CLE can be used to assess response to treatment and different types of treatments, determining differences between subtypes of patients with IBS, evaluate remission, recurrence and prognosis. Also it may clarify a potential mechanism of the pathogenesis and be endoscopic criteria for the diagnosis of the disease. 