A total of 512 colectomy and endoscopic biopsy specimens were reviewed to define the prevalence and possibly the significance of dystrophic goblet cells (DGCs) in neoplastic and nonneoplastic colonic diseases. As compared with an incidence of 1% in disease-free specimens, DGCs were observed in 38% of cases of inflammatory bowel disease, 23% of colonic malignancies, 30% of nonneoplastic polyps, 22% of adenomas, and 8% of cases showing acute self-limited colitis. In contrast, no dystrophic cells were seen in a group of miscellaneous diseases including diverticulitis, diverticulosis, abscesses, fistulas, ischemia, pseudomembranous colitis, melanosis coli, amyloidosis, shock, and mechanical trauma. Although dystrophic cells occur in association with dysplasia and carcinoma, their presence in nonpremalignant lesions, including acute self-limited colitis, raises doubt as to their diagnostic significance. Histochemical studies of the mucin composition in DGCs were unrevealing, failing to show any differences between DGCs and their morphologically normal counterparts in the same region of the colon.