Diarrhea in Adults

Common Causes

• Viral infections like norovirus — These germs can infect the gut and cause sudden loose stools, often called stomach flu. Research suggests it's the top cause of short-term diarrhea in grown-ups (Cleveland Clinic).
• Food poisoning from bacteria — Eating contaminated food might lead to toxins upsetting the stomach. This could happen from undercooked meats or bad water.
• Antibiotics or other medicines — These drugs may kill good gut bacteria along with bad ones, letting diarrhea develop. Antacids with magnesium might also play a role.
• Food intolerances like lactose — The body might struggle to digest milk sugar, causing loose stools after dairy. Fructose issues could do the same.
• Irritable bowel syndrome (IBS) — This gut condition (where bowels act up without clear damage) may trigger diarrhea, especially with stress.

Learn More

For a full overview of this symptom, including home remedies and when to see a doctor, read our complete guide on Diarrhea.