Back to Resource CenterTraveler's Diarrhea


Diarrhea is a change in one's normal stool pattern in which the stool becomes more frequent and less formed. It can occur by itself or along with abdominal cramps, bloating, nausea, vomiting and fever. When diarrhea occurs, the normal function of the intestine is disrupted. Instead of absorbing fluids and nutrients from the material passing through, it reverses that process and secretes body fluids back into itself and passes them out of the body.  

Traveler's Diarrhea is the term used to describe the diarrhea that strikes international travelers from countries with good hygiene to countries that have poor public sanitation and hygiene. It is caused by infection with one of a number of bacteria, protozoa or viruses that are ingested by eating food or drinking water that has been contaminated by stool.  

Dysentery is a more severe form of diarrhea in which white cells and mucus - and occasionally blood - appear in the stool. It usually includes cramps and fever. Dysentery should not be thought of as a separate disease, but simply one end of the spectrum of diarrhea disease.  

Risk of Traveler's Diarrhea  

Your destination is the most important determinant of risk. People who travel from developed countries to developing countries are at risk to accidentally ingest infectious organisms that can cause diarrhea. Studies usually show that 30-40% of people experience an episode of diarrhea in the first 2 weeks of travel in high-risk destinations. Almost all developing countries in Latin America, Africa, the Middle East and Asia are considered high risk. Most countries in Southern Europe and most Caribbean islands are deemed intermediate risk. Low risk areas include the United States, Canada, Northern Europe, Australia, New Zealand and a few of the Caribbean islands.  

Prevention  

You can prevent TD if you can avoid eating food or drinking water that is contaminated with stool. However, this is harder than it might seem in countries with a poor ability to dispose of stool safely. The basic idea is to treat all water as if it is potentially contaminated and to avoid foods that are likely to be contaminated.  

You can lower your risk of getting TD by understanding and using the following guidelines:  

  • Boiling is the best way to make water safe to drink. 
  • All organisms that cause TD are highly susceptible to heat, and they die at temperatures higher than 70°C (158°F). The time it takes for water to reach its boiling point and then return to a temperature below 70°C provides enough contact time to kill all TD-causing organisms - even when altitude is taken into account. Thus, water boiled for any length of time, at any altitude, is safe to drink. 
  • However, the U.S. Centers for Disease Control and Prevention (CDC) takes a more conservative approach, recommending that you bring water to a full boil for 1 minute at altitudes below 6,500 feet (2 km) and for 3 minutes at altitudes above that level. You can improve the taste of boiled water by adding a pinch of salt to each quart or by pouring water back and forth several times between containers to aerate it. 
  • When you cannot boil water, you can disinfect it using chemicals. 
  • Iodine can kill most (but not all) organisms that cause diarrhea, and you can use it to disinfect water, leafy vegetables and fruits. You can also use chlorine, but its ability to kill germs varies greatly with temperature and other factors; thus, it is less reliable than iodine. Iodine and chlorine cannot kill some organisms, including Cryptosporidium and Cyclospora. 
  • To disinfect water with iodine, use tincture of iodine (2% solution). 
  • To disinfect clear water, add 5 drops of tincture of iodine (1 drop = 0.05 ml) to 1 quart or liter of water and let the water stand for 30 minutes before using. 
  • To disinfect very cold or cloudy water, add 10 drops of tincture of iodine to 1 quart or liter of water and let the water stand for several hours if possible. 
  • Tetraglycine hydroperiodide tablets (such as Globulin, Potable-Aqua, Coghlan's), available from pharmacies and sporting goods stores, are also a well-tested method of chemical disaffection. Follow the manufacturer's instructions for use. [Use of trade names is for example purposes only and does not imply endorsement.] 
  • If you want to avoid the taste and smell of iodine in the disinfected water, you can add vitamin C (ascorbic acid) after the iodine has been in contact with the water for 30 minutes or more. Adding about 50 mg of vitamin C to a liter of water and shaking briefly will completely eliminate the iodine taste and odor. 
  • Do not assume that portable filters will make drinking water safe: CDC makes no recommendation about their use because there have not been enough independent studies done to confirm their effectiveness. However, in areas where there is a risk of Cryptosporidium or Cyclospora and boiling all drinking water is not practical, a good quality filter with a pore size of 0.2 microns will eliminate the risk of these 2 organisms. You should then treat the filtered water chemically as well.
  • All bottled or canned carbonated beverages are inherently safe to drink because carbonation makes the drinks acidic, which kills bacteria and other organisms. 
  • Water on the outside of cans or bottles might be contaminated; you should dry wet cans/bottles before opening them and clean surfaces that will have contact with your mouth. 
  • Non-carbonated water that is bottled or canned in developing countries, even if factory sealed, may not be any safer than tap water - remember, tap water should not even be used for brushing teeth. 
  • Hot tea and hot coffee made with boiling water are safe to drink. 
  • Beer and wine are safe to drink, but alcohol added to beverages does not make them safe.
  • Ice is not safe unless it is made from previously treated water - freezing does not kill the organisms that cause diarrhea. 
  • Avoid un-pasteurized milk and milk products (such as cheese), as well as any milk that has not been boiled. 
  • Cooked food must be heated thoroughly and served steaming hot. 
  • Avoid foods such as lasagna, quiche, and casseroles that have been cooked earlier and then served without sufficient re-heating. 
  • Only eat fruit that you can peel yourself. 
  • Avoid salads and uncooked vegetables. 
  • In many areas, human and animal feces are used as fertilizer. The bacteria or parasitic cysts in the feces can contaminate fruits and vegetables grown in the fertilized soil - especially items such as lettuce and spinach that grow at ground level. 
  • Avoid raw or undercooked meat and seafood. 
  • According to CDC, some fish may carry toxins in their flesh and are not guaranteed safe even when cooked. Tropical reef fish, red snapper, amber jack, grouper and sea bass can occasionally be toxic if caught on tropical reefs rather than the open ocean. The barracuda and puffer fish are often toxic and should generally not be eaten. Highest risk areas include the islands of the West Indies, as well as the Tropical Pacific and Indian Oceans. 
  • Food and beverages from street vendors pose a high risk due to potential exposure to insects and a less rigorous sanitary environment. 
  • Breast-feeding is the safest food source for infants who are still nursing. If your child is already weaned, carefully prepare formula with boiled water and sterilized containers. 
  • If a social situation arises in which you may have to accept food that may not be safe to eat, consider selective use of a preventive antibiotic, but only if you clearly understand the risks and benefits of antibiotic use. 

Use of Antibiotics and Antiseptics in Prevention   

Some drugs and other preparations have been shown to be effective in preventing a percentage of TD cases. The most effective method is to take an appropriate antibiotic daily while you travel. This method, however, has the disadvantage of increasing the number of people who have adverse reactions to the drug, and it limits the options for treatment if you get diarrhea in spite of this antibiotic use. Even if you use preventive antibiotics, you may still be at risk for diarrhea and should still follow the food and beverage precautions given above.  

Bismuth subsalicylate (an ingredient of Pepto-Bismol) has been shown to decrease TD by about 60%. However, you have to take up to 8 pills per day, and the medicine can turn your tongue and stools black. Some people who use this drug also have nausea and constipation, and sometimes ringing in the ears. You should not use bismuth subsalicylate if you have an allergy to aspirin, renal insufficiency, or gout - or if you are taking anticoagulants, probenecid or methotrexate. Because bismuth subsalicylate can prevent absorption of doxycycline, you should not use these two drugs together. In people who take salicylates for arthritis, adding large doses of bismuth subsalicylate can produce toxic serum concentrations of salicylate. Bismuth subsalicylate is not approved for use in children under 3 years old, and it should not be given to children and adolescents who have the chicken pox or flu because of the potential risk of Reye's syndrome.  

Self-Diagnosis and Treatment   
Bacteria that are all sensitive to the same type of antibiotic cause the majority of TD cases. Thus, self-treatment is a realistic option for travelers who may not have access to reliable health care while traveling. In fact, many third-world laboratories lack experienced personnel who can reliably identify the organism that's causing your diarrhea. You're often better off treating your best guess than depending on a laboratory for a diagnosis.  

Causes of Diarrhea   

Bacterial Diarrhea  
All cases of diarrhea in the first 1-2 weeks of travel are likely to be due to bacteria. Bacterial diarrhea is characterized by the sudden onset of relatively uncomfortable diarrhea. This usually means that you go from feeling fine to feeling fairly ill within a very short time. You can usually remember the exact time of day when you became ill. Bacterial diarrhea can also be associated with nausea, vomiting, fever or severe abdominal cramps. Bacteria cause 80 to 90 percent of traveler's diarrhea. If you suspect bacterial diarrhea, and you feel ill enough that you can't carry on with your normal plans, you can take an antibiotic to shorten the illness to about one day. There are currently 2 antibiotics that work equally well to treat bacterial diarrhea in adults.  

  • Ciprofloxacin 500 mg twice a day (12 hours apart) for 1-3 days
  • Norfloxacin 400 mg twice a day for 1-3 days

Most people start to feel better within hours of the first dose. Both antibiotics work so rapidly that the current thinking in travel medicine is that travelers should avoid taking drugs to prevent TD but be prepared to take the antibiotic at the onset of bothersome symptoms. Once your diarrhea is gone, stop taking the antibiotic. It is not necessary to complete a preset number of doses when taking these antibiotics for this purpose.  

The following outlines how you might approach treating bacterial diarrhea:  

  • Mild loose stools without other symptoms: Use of an antibiotic is probably not necessary. Use bismuth subsalicylate (Pepto-Bismol) or antimotility drug, such as loperamide (Imodium), if necessary for comfort during sightseeing or travel. Do not use an antimotility drug for more than 48 hours.
  • Moderately loose or frequent stools with cramps or nausea: Take an antibiotic.  Take an antimotility drug if needed for travel or other activities (do not use for more than 48 hours). 
  • Severe diarrhea with intense cramps, nausea, bloody stools, dehydration, or fever and chills: Take an antibiotic. Stay in your room and use the toilet as necessary. Try to avoid taking an antimotility drug unless needed for travel (if taken, do not use for more than 48 hours). Seek medical attention if symptoms do not rapidly improve.

Protozoan Diarrhea  
The risk of acquiring organisms with longer incubation periods, such as Giardia Lamblia (giardia) and Entamoeba Histolytica (amoeba) increases for longer-term travelers. Protozoal diarrhea (giardia and amoeba) is characterized by a more gradual onset of chronic diarrhea. An infected person wakes up with a few loose stools, goes out for the day without difficulty, has another loose stool or two later on, and wonders if something is wrong. Nausea, vomiting or fever is extremely rare. This pattern goes on for another few days or weeks before the person feels ill enough to seek care.  

Giardia tends to produce the same symptoms every day, with an increased amount of gas and a churning feeling in the intestines. Giardia infections in adults can be treated with metronidazole 250 mg 3 times per day for 7 days. In Asia and other parts of the world, tinidazole a single daily dose of 2000 mg (usually 4 pills) for 2 consecutive days.  

Amoebas tend to cause alternating diarrhea and constipation (or at least normal stools) every 2-3 days. Because of this alternating pattern, travelers often think they are getting better every few days and often don't seek medical advice for several weeks. Amoebic infections are the least common (about 1% of travelers). They can be treated with metronidazole 750 mg 3 times per day for 10 days. Tinidazole 2000 mg. dose daily for 3 days followed by a diloxanide furoate (Furamide) 500 mg. tablet 3 times per day for 10 days.  

There are several other organisms that can occasionally cause diarrhea in travelers, such as Cyclospora, Cryptosporidium and Dientamoeba fragilis. A stool exam can lead to a diagnosis if done in a reliable lab, and treatment is available for some of these infections.  

In high-risk diarrhea areas, it is possible to be infected with more than one organism at the same time. A good rule to remember is that vomiting almost always occurs at the beginning of a diarrheal illness and almost never after the diarrhea has been established for a few days. If vomiting occurs in the midst of a diarrheal illness, it probably means you have acquired a new illness.