Abstract
Twenty-four insulin-dependent diabetics, including seven with diabetic diarrhoea, were studied by means of the 14C-glycocholate (14C-GCA) test and various tests for autonomic dysfunction. The breath component of het test was abnormal in four of the seven patients with diarrhoea and one of the other diabetics. Three patients with diarrhoea and a positive breath test result responded to antibiotics, whereas two with diarrhoea and a negative test result did not. High faecal 14C, suggesting bile acid malabsorption, was found in only one patient with diarrhoea and he had previously failed to respond to cholestyramine. These results suggest that bacterial overgrowth in the small intestine does occur in some but not all patients with diabetic diarrhoea and that the 14C-GCA test can predict the response to antibiotics. All the patients with diabetic diarrhoea had good evidence of autonomic dysfunction.