| Due to autonomic neuropathy |
| Abnormal small intestinal motility |
| Bacterial overgrowth |
| Abnormal colonic motility |
| Anorectal dysfunction - lowered rectal sensory threshold, weak internal anal sphincter |
| Increased intestinal secretion |
| Exocrine pancreatic insufficiency (?) |
| Due to associated factors |
| Dietetic foods - sorbitol |
| Concurrent celiac sprue - similar genetic predisposition |
| Bile acid malabsorption (?) |
