The first small bowel diseases have been known for three centuries, but essential breakthroughs have occured in the last twenty years. A new classification may be proposed according to, the physiopathology, the anatomo-pathology, the etiology. From the physiopathological point of view one may separate enterocytic, pre-enterocytic or post-enterocytic malabsorptions. Small bowel injuries described by the pathologist include small bowel resections, villous atrophy, lesion of the lamina propria, or transmural lesions, the vascular pathology and the ulceration of the small bowel. A new syndrome is proposed: the rupture of the cellular continuity or intercellular syndrome.