| Inflammatory/mechanical trauma |
| Reflux esophagitis |
| Cameron lesions |
| Erosive gastritis |
| Gastric ulcer |
| Duodenal ulcer |
| Celiac sprue |
| Whipple disease |
| Meckel diverticulum with ulceration |
| Idiopathic cecal ulcer |
| Crohn disease |
| Ulcerative colitis |
| Mass lesions |
| Carcinoma (any site) |
| Large polyps (any site) |
| Vascular |
| Vascular ectasia(s) |
| Portal hypertensive gastropathy |
| Portal hypertensive enteropathy and colopathy |
| Gastric antral vascular ectasia |
| Hemangiomas |
| Blue rubber bleb nevus syndrome |
| Infectious |
| Hookworm |
| Strongyloidiasis |
| Ascariasis |
| Tuberculous enterocolitis |
| Amebiasis |
| Miscellaneous |
| Long-distance running |
| Factitious |
| Hemoptysis |
| Epistaxis |
| Oropharyngeal |
