Medication use, especially NSAIDs and PPIs, prior to diagnosis is considered a risk factor for MC development. However, the exact pathophysiological mechanism is unclear. It is hypothesized that NSAIDs, PPIs, and SSRIs may have an effect on the colon permeability, due to an idiosyncratic reaction which results in a local immune response. MC patients are considered to be susceptible hosts, prone to react on administration of abovementioned drugs. In order to test this hypothesis and to generate new insights in the pathophysiology of MC, we want to perform an Ussing chamber experiment using fresh colon tissue samples. The primary objective is to assess ex vivo the effect of NSAIDs and PPIs on epithelial permeability of colon biopsy specimens of MC and non-MC patients, using the Ussing chamber system

Inclusion Criteria:

• The indication for colonoscopy is a relapse of MC (active) / MC in remission (remission) / no MC (control)
• Patient is not treated with NSAIDs / PPI / SSRI in week before inclusion

Exclusion Criteria:

• Age below 18 years at the time of diagnosis
• Use of anticoagulants or immunosuppressive drugs
• Severe co-morbidities hindering an endoscopic procedure
• A previous history of any type of chronic colitis, IBS, IBD, colon carcinoma or (partial) colectomy
• A recent (last year) diagnosis of infectious diarrhea or radiation proctitis.
• Use of medication known to influence intestinal permeability
• Excessive alcohol usage (>20 standard units per week)
• Not capable of signing an informed consent