The purpose of this study is to determine whether chromoendoscopy using Indigo-Carmine dye spray is useful in diagnosing microscopic colitis among patients undergoing colonoscopy due to chronic watery diarrhea.

Microscopic colitis is a common disease found in 10% to 20% of cases having chronic watery diarrhea. Obvious endoscopically identifiable changes of the mucosal surface are usually absent, thus diagnosing microscopic colitis relies on multiple biopsy sampling from all segments of the colon. Chromoendoscopy using indigo-carmine dye spray might, however, unravel mucosal changes in microscopic colitis (Suzuki 2011).

The aim of this study is to investigate if chromoendoscopy using Indigo-Carmine 0.2-0.5% in patients with chronic watery diarrhea is useful in diagnosing microscopic colitis.

Inclusion Criteria:

• Patients with chronic non-bloody diarrhea for at least one month

Exclusion Criteria:

• Patients who decline to participate
• Unable to give informed consent