RESUMEN
The term ""collagenous colitis"" was coined by Lindstrom in 1976 to describe the patient with chronic watery diarrhea who had normal rectal mucosa by proctoscopy but who had a thick subepithelial collagenous deposit on biopsy, and now collagenous colitis is recognized as one of the more common causes of chronic diarrhea of obscure origin. But in this country only a few case has been reported. We have seen a 68-year-old man with chronic watery diarrhea with abdominal pain. Physical examination, laboratory and radiologic studies were no abnormal finding. Colonoscopy disclosed grossly normal mucosa through the entire colon but by histologic examination there are chronic inflammation in the lamina propria and thickened subepithelial collagen layer. Symptoms and pathologic findings of patient improved after treatment with sulfasalazine and prednisolone.