Persistent, refractory diarrhoea continues to be an important clinical problem. The mechanisms involved are associated with reduced intestinal absorption and increased intestinal secretion. Reduced intestinal absorption can result from small intestinal resection or from disorders in which there is damage to the small intestine. Motility disorders may also impair absorptive function. The rationale for using octreotide in refractory diarrhoea, intestinal motility disorders, and fistulae relates to its ability to promote intestinal absorption and inhibit gastric, pancreatic, and intestinal secretion. Several clinical studies in patients with short bowel syndrome have reported a reduction of intestinal output in patients taking octreotide compared with controls. Additionally, a number of studies have shown that octreotide improves secretory diarrhoea resulting from neuroendocrine tumours, intestinal infections in AIDS patients, and intestinal graft v host disease. Octreotide may be of use in patients suffering from intestinal motility disorders such as those associated with systemic sclerosis. Octreotide may also be of value in promoting closure of gastrointestinal and pancreatic fistulae.