Irritable Bowel Syndrome: budesonide

INTERVENTION: 3 mg budesonide three times a day (TID) or placebo for two months. Patients will undergo a barostat before and after treatment. Prior to the barostats six rectal biopsies will be taken via a proctoscope. CONDITION: Irritable bowel syndrome (IBS) ; Digestive System ; Irritable bowel syndrome PRIMARY OUTCOME: The effect of budesonide on the rectal sensitivity in IBS. SECONDARY OUTCOME: 1. The effect of budesonide on inflammation in rectal biopsy specimen; 2. The effect of budesonide on IBS‐symptoms INCLUSION CRITERIA: 1. Fulfilling Rome II criteria of Irritable Bowel Syndrome (IBS) 2. 18 to 65 years of age 3. No other organic abnormalities explaining the complaints