Everything you ever wanted to know about traveller's diarrhoea

Although it’s not inevitable that you will get diarrhoea while you are away, it is pretty likely in some destinations. Digestive upsets are the most common travel-related illnesses, affecting about 30-50% of travellers to tropical destinations, so you may as well be prepared.

A man sits in a blue portable toilet with the door open; there is another loo next to his with the door closed. It's in Death Valley so that background is very barren. — Traveller's diarrhoea can stop you in your tracks, so it's best to try and avoid it. ViewApart / Getty Images

What causes diarrhoea?

Your risk of getting ill mainly depends on how likely it is that the food and drink you are consuming is contaminated with disease-causing microorganisms. That said, roughly one third of cases are due to non-specific causes such as stress, jet lag and changes in eating habits. If you’re roughing it, and eating from small stalls and restaurants where hygiene is more likely to be a problem, you’re more likely to catch something. If you are away on a long trip, there’s a higher chance you will get ill at some stage.

Fact vs fiction

Not surprisingly, you’ll find diarrhoea a hot topic of conversation among travellers, and it can be hard to separate fact from fiction at times. Just remember:
- Travellers diarrhoea is generally a short, mild illness lasting on average about three to five days
- Replacing lost fluids and salts is the most important part of treating any watery diarrhoea, whatever the cause
- You don’t usually need to get medical advice or antibiotic treatment for mild to moderate diarrhoea
- There are certain situations when antibiotics need to be used – in these situations it’s best to get medical advice

Shot from above, this image looks down on a street vendor selling food from a dozen large aluminium bowls; there are half a dozen people crowded around the stall, while others (blurred) walk past. — Street food has its tasty rewards, but it can often have unintended consequences. Anansing / Shutterstock

Avoiding diarrhoea

Although we don’t want to deprive you of a fascinating talking point during your travels, it’s obviously best to avoid getting diarrhoea in the first place. Unhygienic food preparation practices and contaminated water are common causes of travellers diarrhoea. It sounds gross, but basically you get diarrhoea by eating other people’s faeces through contaminated food, water and eating utensils. Hands used to prepare food may not have been washed thoroughly after toilet duty. Flies carry dirt and microorganisms on their feet. In dusty, urban areas, tonnes of dry faecal matter floats around in the atmosphere, and this can land on food left sitting around.

You can also get diarrhoea from direct contact with an infected person (if you touch hands etc that haven’t been washed adequately) or from swimming in contaminated water (by swallowing small amounts). Some infective agents such as Giardia can survive even in chlorinated water, and rivers and oceans may be contaminated with sewage.

A smiling woman grabs a foil-wrapped meal from the hands of a vendor who is leaning out of a food truck. — Direct contact with anyone who hasn't washed their hands (or eating food prepared by them) can result in catching diarrhoea. RyanJLane / Getty Images

Types of diarrhoea

Different microorganisms cause different types of diarrhoeal illnesses, which may need to be treated in different ways. The most important things to look out for are: a high body temperature, blood in your faeces and how severe the diarrhoea is (ie how often you have to go to the toilet).

Watery diarrhoea This is the type of diarrhoea you’re most likely to get when you are away. The cause varies with your destination, but it’s usually bacterial, often a strain of a bacteria called Escherichia coli. Relatives of this microbe are normal residents of your gut, but this is a strain that has turned nasty.

The usual scenario is that the illness starts a few days after you arrive, and involves up to six episodes of loose faeces a day. You may feel sorry for yourself, but it doesn’t usually make you feel particularly unwell. If you get a fever with it, it’s usually low (less than 38°C). Nausea and vomiting are common, especially at the start, but it’s not a major feature of the illness (compare this with food poisoning). Stomach cramps, bloating and frequent gas are also common.

The illness generally resolves itself in a few days (on average three to five). It rarely causes severe dehydration, although the potential is always there and is more of a risk in children and older travellers. Don’t panic and start stuffing yourself with medications. The most important treatment measure is to avoid dehydration by replacing lost fluids and salts, which you should start doing straight away.

A toilet in the middle of a dense rainforest in British Columbia, Canada; there are no walls, just a white seat on a green platform surrounded by trees. — Thankfully toilets are not always as far away as they might seem when diarrhoea hits; this one is found in the forests of British Columbia, Canada. Susan Breau / 500px

Bloody diarrhoea (dysentery) Dysentery is any diarrhoea with blood in it. It can be more severe and protracted than the more common watery diarrhoea described earlier, and usually needs antibiotic treatment. Out of every 10 travellers who get diarrhoea, only about one will have dysentery. The most common cause is one of a number of bacteria, including various shigella and salmonella species.

Dysentery usually begins with nonspecific flu-like symptoms, and you often feel really rough, with headache, high fever (38°C and above), and aches and pains all over. To start with, the diarrhoea is often watery and in large quantities; later it gets less and you start to notice blood and mucus (slime) mixed in your faeces. Painful stomach cramps are often a feature of the illness, usually heralding a dash to the little room.

Get medical advice if you have dysentery, as you’ll need a laboratory test and a course of antibiotics. In the meantime, rest and make sure you drink plenty of fluids.

A toilet on top of MacKinnon Pass, Milford Track, New Zealand; it overlooks a fog-filled valley lined by jagged peaks. — Another rescue loo with a view; this one is located on top of MacKinnon Pass, Milford Track, New Zealand. Patrick Munz / 500px

Vomiting & diarrhoea If you suddenly get an attack of nausea and profuse vomiting soon after eating, it’s probably due to food poisoning. This is a worldwide problem that is more likely when you’re eating food not prepared by yourself, especially where food preparation and storage procedures may be suspect.

Vomiting is the main symptom, often with stomach cramps and some watery diarrhoea later. You may have a suspicion that you’ve eaten something that wasn’t fresh (such as sea food); another clue is if everyone who ate the same thing comes down with the same illness.

No specific treatment is needed as a rule. You should rest, sip fluids if possible, and wait for it to settle down, which it should start doing in about 12 to 24 hours. Generally, it’s best to avoid anti-vomiting medication, as vomiting is your body’s way of getting rid of the bad stuff. You should seek medical help urgently if the illness doesn’t settle down within 24 hours, if it gets much worse, if there’s any blood in the vomit or diarrhoea, if you have a high fever or if you have very severe stomach pains or a severe headache.

How to deal with diarrhoea

If diarrhoea strikes, you don’t necessarily need to reach for your medical kit for "stoppers" (see 'Antidiarrhoeal remedies' below) which paralyses the gut and stops the flow, or for antibiotics; there are some simple measures it’s worth taking:
- Rest, which gives your body the best chance to fight whatever is making you ill; in any case, being on the move with diarrhoea presents a few logistical problems
- Drink plenty of fluids
- Take your temperature and note what it is; repeat this to see how the illness is progressing
- Examine what’s coming out of your guts to check for blood or mucus (slime)
- Be aware of how often you’re passing urine and what colour it is, so you can check you’re not getting dehydrated
- Note any other symptoms you may have: diarrhoea can occur in many other illnesses, including malaria and hepatitis
- Remember that diarrhoea is contagious so be scrupulous about washing your hands after you use the toilet

A plastic glass of water sits on a table track on the back of an airplane seat. — When diarrhoea strikes when travelling, keeping hydrated is a key to recovery. cristianl / Getty Images

What to drink when you have diarrhoea

You need to replace what’s being lost through the diarrhoea and any vomiting: mainly salts (sodium, potassium and chloride) and water. Sachets of oral rehydration salts (ORS) are readily available worldwide and contain optimum amounts of glucose and salts. There’s no magic ingredient in ORS, but the relative quantities of salt and sugar are important. You can make up your own solution if necessary by adding six teaspoons of sugar (or honey) and half a teaspoon of table salt to 1L of boiled water. Make it more palatable by adding any flavour you like, for example lemon, ginger or orange juice.

Alcohol, strong tea, coffee and other caffeine-containing drinks (such as colas) are all best avoided because they can irritate the gut and promote fluid loss. It’s best to steer clear of dairy products while you have diarrhoea – you can get an intolerance to the sugar in milk when you have diarrhoea, which then exacerbates the problem.

Antidiarrhoeal remedies

There are remedies you can take to stop the flow if you get diarrhoea, but as a general rule, you’re better off allowing the illness to run its course. Antimotility drugs (ie "stoppers") like loperamide (often sold as Imodium), diphenoxylate (with atropine) and codeine phosphate slow down your guts, reducing the number of times you have to visit the little room. These are sold under a wide variety of brand names and are usually available without prescription. Stoppers can be useful if you have to travel on a toilet-less mode of transport or attend an important meeting, but you should treat them with a bit of respect. If you do need to take them, be careful not to take more than the recommended dose.

Bismuth subsalicylate (Pepto-Bismol) can be useful in treating diarrhoea, although it is less effective than the antimotility drugs. Bismuth shouldn’t be taken if you have asthma or if you are taking aspirin, are sensitive to aspirin or have been told to avoid aspirin for any reason. Alternatively, peppermint oil is an antispasmodic that may be helpful if you’re experiencing abdominal cramps. It has no serious side effects. Some herbal teas available locally may be helpful for soothing stomach cramps.

Stethoscope isolated on a white background. — If you have dysentery, a fever or if your diarrhoea hasn't subsided in 48 hours, you should consider seeking medical help. piotr_pabijan / Shutterstock

Antibiotics

If you are seriously ill or the diarrhoea just won’t go away, you’ll probably need antibiotic treatment. In this situation, you should seek medical advice on the most appropriate treatment and you may need a laboratory test to determine the cause of your illness. Remember that most cases of travellers diarrhoea do not need treatment with antibiotics, and will clear up on their own in a few days.

Whether or not to treat simple watery diarrhoea with antibiotics is much less clear-cut, and it’s an issue the experts can’t agree on. There’s plenty of evidence to show that taking a dose of an antibiotic (such as ciprofloxacin 500mg, single dose) with loperamide (an antimotility drug) can reduce the length of a diarrhoeal illness quite dramatically. Because of this, some doctors will advise you to carry a treatment dose of an antibiotic to take as soon as you develop diarrhoea. Others, however, argue that the benefits are not offset by the risks (including possible side effects of the antibiotic and the emergence of bacterial resistance) and that in any case diarrhoea in travellers is usually a mild illness that will clear up quickly enough on its own. On balance, it’s probably worth having a course of antibiotics with you, but keep it for a bad attack of watery diarrhoea (dashing to the toilet more than about six times a day).

Travel safely and diarrhoea-free!