Cryptogenic multifocal ulcerative stenosing enteritis/enteropathy (CMUSE) and chronic nonspecific multiple ulcers of the small intestine (CNSU) are descriptive names of inflammatory pathology of unknown origin, with multiple ulcerative strictures confined to the small bowel. Although they share many clinical features, it was suspected from early on that CMUSE and CNSU are distinct enteropathies, within the same spectrum of nonspecific multiple circumferential ulcerations within the small intestine. These pathological conditions were believed to be first described at the end of the 1950s, beginning of the 1960s both in Spain, in France and in Japan based on surgical resection specimens of small-bowel segments of patients who presented with chronic abdominal pain, subobstruction and iron-deficiency anaemia [[1], [2], [3]]. However, older case series with similar primary nonspecific ulcers of the small bowel, not related to Crohn's disease or intestinal infections, were already described by the Mayo Clinic in Rochester, USA and probably also represent CMUSE patients [4,5]. Histopathological examination of the resection specimens of these early cases revealed multiple superficial and annular mucosal ulcerations extending into the submucosa without transmural inflammation. The ulcerations induced short circumferential strictures, 5–15 cm apart with normal intestinal mucosa in between and a non-specific inflammatory infiltrate without granulomas or Koch's bacilli. Surgical resection of the affected small bowel segments was the only treatment option available [[1], [2], [3], [4], [5]]. Back then, diagnosis was difficult since small bowel follow-through radiological examination and even diagnostic laparotomy often turned out negative [[1], [2], [3], [4], [5]]. Since then, a vast increase of medical publications describing CMUSE and CNSU cases and case series emerged from the mid years 2000 on with de advent of wireless videocapsule endoscopy and balloon-assisted enteroscopy, opening up the black box of the poorly accessible small bowel [6]. Most CMUSE case reports and case series originate from Europe and the far East, whereas CNSU was initially exclusively diagnosed in Japan (Table 1, Table 2). Only recently CMUSE was ‘rediscovered’ in the USA and CNSU was also diagnosed outside Japan [29,31,55,56,58,63,65,66,68,69].