The holiday is booked, the anticipation is building, and yet your gut can throw a spanner in the works. Find out here why traveller's diarrhoea is so common, how you can prevent it with diet and simple hygiene measures, and why a synbiotic should also have a place in your luggage.

Depending on the destination, about one in three travellers develops diarrhoea. Traveller's diarrhoea is particularly common in regions with lower hygiene standards, such as parts of Asia, Africa, Central and South America. However, the risk cannot be completely ruled out in other holiday countries either.

The good news is that with good preparation, some attention to food choices and a gut-friendly diet, you can do a lot to reduce the risk. For years, research has also been concerned with the question of whether the intestinal microbiome can be specifically supported before the start of the journey, e.g. with probiotics.

What exactly is traveller's diarrhoea?

Professional bodies define traveller's diarrhoea when at least three unformed or watery stools occur within 24 hours on vacation. Other symptoms often include:

• Abdominal cramps
• Nausea
• Flatulence
• Vomiting
• sometimes also slight fever

In most cases, the symptoms subside within a few days. Nevertheless, they can derail your holiday. If you spend several days with diarrhoea, you not only lose valuable vacation time, but often also large amounts of fluid and electrolytes.

Why do so many people get diarrhoea on vacation?

Many initially suspect spoiled or unusually spicy food as the cause. In fact, the picture is much more complex. In most cases, several factors come together that temporarily throw the intestine out of balance. The results of various studies are not always consistent, but at the same time it is increasingly becoming apparent that it is not individual bacteria that are decisive, but the interaction of the entire microbial ecosystem.

Unfamiliar diet

On vacation, different foods often end up on the plate than at home. More fat, hot spices or fermented specialties pose new challenges for the intestines. For most people, this is completely unproblematic. However, in more sensitive individuals, the change can contribute to flatulence, abdominal pain or digestive problems.

This is not about avoiding typical local dishes. On the contrary, they are often among the most beautiful holiday experiences. It just makes sense to give the digestive system some time to adapt, especially in the first few days.

The intestine encounters unknown pathogens

The most common trigger for traveller's diarrhoea are bacteria, especially so-called enterotoxigenic Escherichia coli (E-Coli or ETEC). They produce toxins that can cause the intestines to release large amounts of water. Watery diarrhoea is the result.

In addition, other pathogens can also be responsible, for example:

• Campylobacter
• Salmonella
• Shigella
• Noroviruses
• Rotaviruses
• Parasites such as Giardia lamblia

These microorganisms occur in different frequencies depending on the country of travel. However, this does not mean that the food is fundamentally "bad". Rather, our immune system encounters germs it hasn't come across before.

Contaminated water and food

It is not only tap water that can be problematic. Pathogens often enter the body through food.

The following can be particularly critical:

• Ice cubes made from tap water
• Salad washed with tap water
• Unpeeled fruit
• Raw seafood
• Meat that is not fully cooked
• Dishes that are left unrefrigerated at the buffet for a long time

That's why a simple rule still applies when traveling, which has lost none of its relevance despite its age: "Boil it, cook it, peel it or forget it."

Stress also travels with you

The holiday doesn't just start on the beach. Long car journeys, time differences, little sleep, heat or unfamiliar daily routines also mean stress for the intestines.

Via the gut-brain axis, the brain and digestion are in constant exchange. Physical and psychological stress can alter intestinal movement, affect the permeability of the intestinal barrier and affect the composition of the gut microbiome. This could make the intestine more susceptible to pathogens.

This is precisely why many people report that the symptoms begin shortly after arrival, even before they have eaten any particularly exotic food.

How to prevent traveller's diarrhoea

Unfortunately, there is no such thing as one hundred percent security. Even people who follow all hygiene rules can fall ill with traveller's diarrhoea. Nevertheless, studies show that the risk can be reduced by taking a few simple measures.

Maintain good food hygiene

The most important recommendations are also the simplest:

• Wash hands regularly with soap and water
• Use hand disinfection if there is no washing facility
• Drink only bottled or boiled water
• Order drinks without ice cubes if possible
• Peel your fruit
• Eat meat, fish and eggs only if they have been well cooked
• Choose dishes that are freshly prepared and served hot

These measures may sound obvious, but they are still among the most effective ways to prevent issues.

Support your gut microbiome before the trip

Our gut is home to trillions of microorganisms that together make up the gut microbiome.

These tiny roommates do amazing things every day: they help with digestion, produce metabolic products and some vitamins, support the intestinal barrier, are in close contact with the immune system and even influence processes related to our mental well-being via the gut-brain axis. This makes it all the more important to support this sensitive ecosystem as well as possible, especially before a trip.

This is how you can pay some attention to your intestines before you start your trip:

• a varied, plant-based diet
• Sufficient fibre from vegetables, fruit, whole grain products and legumes
• Fermented foods such as natural yoghurt, kefir or sauerkraut
• Drink enough (in summer 2.5 to 3 litres of unsweetened drinks)
• Meals spread over the day as regularly as possible

A diverse diet provides the intestinal bacteria with the nutrients they need for their metabolic processes. This can also help improve their resistance to external stresses.

Can probiotics and synbiotics prevent traveller's diarrhoea?

The role of probiotics and synbiotics in the prevention of traveller's diarrhoea has been studied for many years.

While probiotics contain live microorganisms, synbiotics combine probiotics with prebiotics, which serve as food for beneficial gut bacteria.

The studies so far provide a mixed picture. Some systematic reviews and meta-analyses suggest that certain bacterial strains may reduce the risk of traveller's diarrhoea. However, since very different preparations, dosages and study designs were examined, the results can only be compared to a limited extent. International guidelines therefore do not currently make any general recommendation for the preventive use of probiotics or synbiotics.

However, this does not mean that they are inherently ineffective. In fact, individual, well studied bacterial strains absolutely could have a benefit. If you want to specifically support your intestines before a trip, you may wish to consider a high-quality synbiotic as a supplementary measure. It is important to have realistic expectations: It does not replace careful food hygiene, nor does it offer guaranteed protection against traveller's diarrhoea.

What belongs in the first-aid kit

Even with good preparation, traveller's diarrhoea cannot always be prevented. This makes it all the more sensible to be well equipped for emergencies.

• Electrolyte solutions to drink to compensate for fluid and mineral losses in diarrhoea.
• Hand sanitiser for if water and soap are not available on the way.
• Regularly needed medication in sufficient quantities.
• If necessary, a remedy for diarrhoea, after consultation with a doctor or pharmacy, especially in the case of long-distance travel or pre-existing conditions.
• Activated charcoal (charcoal tablets), which is traditionally often used for diarrhoea. It can bind substances in the intestine, but the scientific evidence for a reliable effect on infectious traveller's diarrhoea is limited, and always check for any contraindications with regular medications.
• Optional: a high-quality synbiotic, such as BioMe+, if you want to support your gut microbiome before and during the trip.

In the case of any diarrhoea, especially if severe, the first priority is fluid balance.

Ensuring you are drinking enough is more important than eating. As soon as the symptoms improve, you can slowly start eating easily digestible foods again.

When should you seek medical attention?

Most cases of traveller's diarrhoea will resolve on their own within a few days. However, there are situations in which you should seek medical help.

These include, but are not limited to:

• High Fever
• Blood in the stool
• Severe or persistent abdominal pain
• Signs of severe dehydration, such as dizziness, very dark urine, or severe circulatory weakness
• Diarrhoea that lasts longer than two to three days or worsens significantly

In these cases, do not hesitate to seek medical help.

This is especially true in tropical travel countries, where other infectious diseases can occur in addition to the classic pathogens.

Conclusion

While traveller's diarrhoea is one of the most common travel illnesses, it doesn't have to be an inevitable holiday souvenir. With good food hygiene, a mindful diet and conscious preparation, you can do a lot to reduce the risk.

Research on the gut microbiome also provides exciting insights. It is true that the studies to date are not yet sufficient to recommend probiotics or synbiotics in general for the prevention of traveller's diarrhoea. However, numerous individual studies indicate that certain bacterial strains could have a positive influence.

As such, it can make sense to make sure to support the intestines before a trip. After all, it has to adapt not only to new foods on the way, but also to other microorganisms, climatic conditions and often stress and lack of sleep.

Let's be honest: Hopefully, we would all rather be left with beautiful memories, amazing photos and delicious culinary discoveries from our holidays, instead of days we would rather forget.

Sources

• Centers for Disease Control and Prevention (CDC). Yellow Book 2026: Traveller's diarrhoea.
• Alharbi A. et al. (2024). Probiotics for the prevention of traveller's diarrhoea: A systematic review.
• Fan Y. et al. (2024). Network meta-analysis of interventions for the prevention of traveller's diarrhoea.
• Biała K. et al. (2025). Traveller's diarrhoea – prevention and treatment with probiotics and antibiotics.
• German Society for Tropical Medicine, Travel Medicine and Global Health (DTG): Recommendations for travel medicine.