The rather vague term "benign granuloma of the intestine" included in the past a variety of chronic inflammatory lesions which, while resembling grossly new formations, were neither neoplastic nor due to any specific organism. The exhaustive review of literature by Tietze1 in 1920 and later reports by Moschcowitz and Wilensky2 and by Mock3 served to revive interest in the subject without, however, contributing new concepts. In 1932 Crohn4 and his associates presented for consideration a definite pathologic and clinical entity which they term "regional ileitis." This new concept was based on a clinical study of fourteen cases and a study of pathologic alterations seen in thirteen resected specimens. The lesion described involved the last 25 to 35 centimeters of the ileum, terminating abruptly at the ileocecal valve. The involved segment is greatly thickened, heavy and reddened. The lumen of the bowel is irregularly distorted and narrowed.