Introduction Carcinoma of the large bowel has been found significantly more often in chronic ulcerative colitis than in the general population of the same age, sex, and race.1 Before this conclusion was reached a variety of questions had to be answered: 1. What is the "normal" frequency of polyps and carcinoma of the large bowel? 2. What are the possibilities of malignant transformation of an adenomatous polyp? 3. What are the chances that inflammatory pseudopolyps could undergo further evolution into an adenoma and into a malignant growth? The information obtained from the literature on this important subject has been summarized in this brief review. There is a continued interest in the nature and cause of polyps of the large intestine.2-7 The frequency of polyps on routine proctoscopic examinations at the University of Chicago Clinics was 5.4%.8 Single polyps were found in 88% of the cases; multiple polyps,