What causes traveller's diarrhoea?

Changes in local sanitation, food handling, and water treatment can expose a traveller to germs their body has not encountered before. Risky sources include untreated drinking water, ice made from unsafe water, raw foods washed with contaminated water, undercooked meat or seafood, and food kept at an unsafe temperature. The same exposure may cause food poisoning, with diarrhoea, abdominal cramps, nausea, or vomiting.

The illness often starts during a trip or soon after returning. The main concern is fluid loss. Loose stools can remove water and salts from the body, especially when vomiting or fever is also present.

Drink frequent small amounts of safe fluids. Oral rehydration solution can replace water and salts more effectively than plain water when diarrhoea is frequent. Eat light foods as tolerated, and avoid alcohol until you are recovering. Wash your hands carefully and avoid preparing food for other people while symptoms continue.

For future travel, choose sealed drinks, fully cooked food served hot, and fruit you can peel yourself. A clinician or pharmacist can advise whether an anti-diarrhoeal medicine is suitable; some medicines are not appropriate with fever or blood in the stool.

Seek urgent medical help for severe dehydration, fainting, confusion, inability to keep fluids down, severe abdominal pain, or blood in the stool. Contact a clinician if fever is significant, symptoms are worsening, or diarrhoea does not begin to settle after a short period. People who are pregnant, older, immunocompromised, or living with a long-term illness may need advice earlier.

Ask: Could this be food poisoning? What signs of dehydration should I monitor? Do I need a stool test or prescription treatment? Which fluids and medicines are appropriate for me?