Traveller's diarrhoea is the most common travel-related illness, affecting an estimated 20–60% of international travellers depending on destination, according to NHS Fit for Travel. Community pharmacists are often the first point of contact for pre-travel advice and for supplying self-treatment options.
What causes it
The condition is most commonly caused by enterotoxigenic Escherichia coli (ETEC), but can also result from other bacteria (Campylobacter, Salmonella, Shigella), viruses (norovirus, rotavirus) or parasites (Giardia, Cryptosporidium). High-risk destinations include South and South-East Asia, Central America, West and East Africa and the Middle East.
Transmission is almost always through contaminated food or water, including ice made from untreated water and salads washed in it.
Prevention advice pharmacists can give
The "boil it, cook it, peel it, or forget it" principle remains the cornerstone of prevention, according to UKHSA travel health guidance:
- Drink bottled or boiled water only. Check that bottle seals are intact.
- Avoid ice in drinks unless made from purified water.
- Eat freshly cooked, hot food. Avoid buffets that have been sitting at room temperature.
- Peel fruit yourself. Avoid pre-prepared fruit salads and salads in general.
- Be cautious with street food. High turnover stalls cooking to order are generally safer than those with pre-prepared dishes.
Hand hygiene is equally important. Alcohol-based hand gel (at least 60% alcohol) should be used when soap and water are unavailable, though it is less effective against some viruses such as norovirus.
Water purification tablets
Pharmacies stock chlorine-based and silver-ion water purification tablets. These are useful as a backup for trekkers and travellers in remote areas. Chlorine-based tablets (e.g. containing sodium dichloroisocyanurate) are effective against most bacteria and viruses but have limited activity against Cryptosporidium. Advise filtering water first if it is visibly cloudy.
Self-treatment: what to supply
Oral rehydration salts (ORS)
Fluid replacement is the priority in managing traveller's diarrhoea. ORS sachets (containing glucose and electrolytes formulated to WHO standards) should be recommended to all travellers visiting high-risk destinations.
Key counselling points: dissolve one sachet in the specified volume of clean water; sip frequently rather than drinking large volumes at once; continue normal fluid intake alongside ORS; and discard any prepared solution after 24 hours if not refrigerated.
For adults, ORS is supplemented by maintaining regular fluid intake — clear soups, diluted fruit juice and clean water all contribute. The BNF advises that in adults, ORS is less critical than in children, but remains beneficial.
Loperamide
Loperamide 2mg capsules are the standard antimotility agent for symptomatic relief. According to BNF guidance, the adult dose is 4mg initially, followed by 2mg after each loose stool, up to a maximum of 16mg daily for up to two days.
Important counselling points:
- Loperamide treats symptoms only — it does not address the underlying infection.
- It should not be used if the patient has bloody diarrhoea (dysentery) or a high fever, as slowing gut motility may worsen an invasive bacterial infection.
- It is not recommended for children under 12 years without medical advice.
- It can be used alongside ORS.
Standby antibiotics
Some travellers are prescribed standby antibiotics (commonly azithromycin or ciprofloxacin) by their GP or travel clinic. Pharmacists should clarify that these are prescription-only medicines and cannot be supplied OTC. However, pharmacists can reinforce the prescriber's instructions: use only if symptoms are severe (fever above 38.5°C, bloody stools, or dehydration not responding to ORS) and seek local medical advice if symptoms persist beyond 48 hours of antibiotic use.
When to refer
Travellers should seek medical attention locally if they experience:
- Blood or mucus in stools
- Fever above 38.5°C
- Persistent vomiting preventing fluid intake
- Symptoms lasting more than 72 hours without improvement
- Signs of significant dehydration (dizziness, dark urine, confusion)
- Diarrhoea in a child under 2 years
On return to the UK, a GP appointment is appropriate if diarrhoea persists beyond 7–10 days or recurs, as parasitic causes such as giardiasis require specific treatment.
Pharmacy's role in travel health
Community pharmacies offer accessible pre-travel advice without a GP appointment. Many pharmacies also provide travel vaccinations and can signpost travellers to specialist travel clinics for high-risk destinations. Use PharmSee's job search to explore pharmacy roles in travel health services.
Sources: NHS Fit for Travel, BNF Acute Diarrhoea treatment summary, UKHSA Travellers' Health guidance.