Our study was directed not only towards the diagnosis of small bowel Crohn's disease, but especially to a quantitative analysis, for a correct therapeutical approach. This experimental trial is based on the relationship between radiological evidence, measured during small bowel enema, and the seriousness of the morphological and functional damage to the intestinal mucosal membrane, evaluated with a post-heparin diamine-oxidase activity test. With this method we studied 35 selected patients; 16 of them were affected by the disease with an exclusive localization in the small bowel and 5 have been considered separately, because 3 patients had already been operated and the other 2 showed different localizations. In our results, the two parameters were not constantly related to each other. In other words the enema's morphological data sometimes do not accord with the mucosal membrane integrity index expressed by the enzyme. Anyway the importance of this study is the attempt of making an objective comparison between an anatomic situation and its functional consequence. These aspects have a great significance in Crohn's disease.