Causes of Diarrhea

Diarrhea - loose watery stools three or more times a day - is the gut's emergency flush response. Almost everything that causes it arrives through the mouth, which is why prevention is mostly about what goes in.

The infectious causes (the majority)

• Viruses: rotavirus in infants, norovirus in everyone - the commonest cause worldwide, self-limiting
• Bacteria: E. coli, Shigella, Salmonella, Campylobacter, cholera - from contaminated water, food and hands; these bring fever and sometimes blood
• Parasites: Giardia (the chronic bloating-traveler), amoeba (bloody mucus dysentery)
• The route is always the same: contaminated water, undercooked or street food kept warm too long, unwashed hands, unwashed raw produce

The non-infectious causes

• Food intolerances: lactose intolerance (milk triggers bloating and loose stools) is common in Indian adults
• Medicines: antibiotics (they clear gut bacteria along with the infection), antacids with magnesium, metformin, chemotherapy