At the outset of the research programme into irritable bowel syndrome (IBS) it was perceived that there was a need to develop a symptom-based classification for the patients. Four groups of patients were identified, those with spastic colon syndrome, diarrhoea-predominant spastic colon syndrome, functional diarrhoea and midgut dysmotility. While working with outpatients with IBS it was noted how some of them had suffered symptoms for many years; specifically, a group of patients satisfying the criteria for midgut dysmotility had also suffered from particularly severe and intractable intestinal symptoms. These patients underwent 24 h ambulatory studies of small intestinal motility and the majority were found to have manometric features of chronic idiopathic intestinal pseudo-obstruction (CIIP). To characterise the cause, laparoscopic full-thickness small intestine and colonic biopsies have been obtained in forty-five of the latter group of patients. Of these patients 58% have been found to have complete or partial deficiency of α-actin epitope staining in the inner circular layer of small intestinal smooth muscle. This deficiency is believed to represent an important biomarker rather than the cause of CIIP, since α-actin epitope deficiency has been observed in association with enteric neuropathy and myopathies. In relation to the management of CIIP patients, a multidisciplinary model is proposed incorporating management of co-morbid psychological and psychiatric pathology, abdominal and musculoskeletal pain, fatigue, urological symptoms and nutrition. A six-stage nutritional management plan for these patients is presented.