We present in this article the cases of two women afflicted with aqueo
sus chronic diarrhea with normal analysis, radiology, and endoscopy, b
ut presenting sigmoid biopsy of collagenous colitis. One of them was t
reated with omeprazol and the other with corticoids. Despite not havin
g found anomalies in the endoscopy, we reccomend the practice of recto
sigmoid biopsy in all cases of chronic diarrhea.