Read condition-specific symptoms and clinical context for Escherichia coli. Many strains are harmless residents. Some cause diarrheal illness.
E. coli can live in the human intestine. Most kinds are harmless, while some cause illness. This profile covers diarrheagenic strains: disease potential and symptoms depend on the strain, rather than the species name alone.
Possible symptoms of disease-causing intestinal strains; these do not describe ordinary gut carriage.
Possible symptoms: Watery or bloody diarrhea; Strong abdominal cramps; Sometimes vomiting; Sometimes a low fever.
CDC advises contacting a clinician for bloody stool, dehydration, or diarrhea or vomiting lasting more than two days. HUS is a medical emergency.
Many E. coli strains are harmless members of the human intestinal community. This differs from diarrheal disease.
No diarrheal symptom list is assigned to ordinary carriage. Strain and clinical context matter.
The species name alone does not establish an infection.
Source check: 2026-09-19. Educational content; independent scientific review remains pending.