Eosinophilic gastroenteritis, a condition of unknown etiology, has frequently been reported involving the stomach and small bowel. The colon is rarely cited as a site for the condition; however, a review of the literature reveals over 20 cases (including ours). The findings indicate that the colon is now a recognized, but rare, site of involvement and that the condition can be diagnosed via the colonoscope. No clear-cut etiology can be defined, but the presence of allergy (33 percent) and of the herring worm (two cases) is noted.