The enteric coated KCl tablet formulation generates complications that affect selectively the small intestine. A novel 1 g KCl tablet preparation proved to be accountable for the development of a specific type of intestinal disease. 11 cases of stenotic ulcers of the proximal ileum have been treated at the Clinique chirurgicale "C" (CHRU, Nancy) since January 1986, 9 of them presenting with perforations. These 11 patients required potassium replacement, which was being supplied by the same tablet formula. A study of these 11 cases focusing on the patients history and clinical characteristics was carried out, that included both macroscopic and microscopic examinations of the lesions. Arterial and venous networks were visualized by X-ray in two surgical tissue specimens, respectively, following injection of contrast material. The authors were thus able to bring forth evidence of the clinical uniqueness (prodromal pain reminiscent of König's syndrome and peritonitis characterized by asthenia); to identify the main risk factor (i.e., reduced bowel movement); as well as describe the basic lesion (pylorus-like stenosis), and propound a novel theory concerning the etiology and the pathology of this condition. The observation of the aforementioned cases initiated a nation-wide, post-marketing pharmacological survey, which resulted, as did a similar investigation which had been carried out in the States, in the discontinuation of any treatment by this type of galenic form of the product.