| Inflammatory |
| Ulcerative colitis |
| Crohn's colitis |
| Infectious |
| Bacterial |
| Clostridioides difficile pseudomembranous colitis |
| Salmonella - typhoid and nontyphoid |
| Shigella |
| Campylobacter |
| Yersinia |
| Parasitic |
| Entameba histolytica |
| Cryptosporidium |
| Viral |
| CMV colitis |
| Self-limited colitis (culture negative) |
| Other |
| Pseudomembranous colitis secondary to methotrexate therapy |
| Kaposi's sarcoma |
