A 40-year-old physician experienced abdominal pain, loose stools, hematochezia, and anal discomfort with defecation associated with the daily consumption of 15 to 30 whole peanuts, including the shells. Thorough evaluation revealed only nonspecific colitis of the distal portion of the sigmoid colon and inflamed hemorrhoids. Discontinuation of whole peanut ingestion was associated with symptomatic, endoscopic, and histological resolution. In this patient, undigested peanut shells seem to have caused a nonspecific colitis, perhaps as the result of mechanical abrasion of the colonic mucosa.