| Complication | Prevalence (percent) |
| Intestinal | |
| Proctitis or rectal prolapse | * |
| Toxic megacolon | 3¶ |
| Intestinal obstruction | 2.5¶ |
| Colonic perforation | 1¶ |
| Systemic | |
| Bacteremia | 4 |
| Moderate to severe hypovolemia | 10 to 12¶ |
| Hyponatremia | 29¶ |
| Leukemoid reaction | 3¶ |
| Neurologic symptoms | 12 to 45 |
| Reactive arthritis or Reiter syndrome | 1.4 |
| Hemolytic-uremic syndrome | <1 |
