| Factitious diarrhea (laxative abuse) |
| Rectal villous adenoma |
| Neuroendocrine tumors |
| VIPoma |
| Carcinoid syndrome |
| Gastrinoma (Zollinger-Ellison syndrome) |
| Lymphocytic or collagenous colitis |
| Congenital diarrhea |
| Bile salt enteropathy |
| Enterotoxic Escherichia coli |
