Robin considered herself a seasoned traveler. She'd been south of the border before, so when she visited a friend in Mexico City, she knew better than to drink the water. But she let her guard down at a dance club in Acapulco and had a drink "on the rocks." She spent the next seven hours on a bus battling traveler's Diarrhea (TD). "The discomfort was excruciating," Robin adds.

Traveler's diarrhea is one the most common illnesses affecting travelers. Travelers who ingest contaminated food or drink may experience a range of symptoms—including watery diarrhea, nausea, vomiting, fever, and abdominal pain—that can last for 3-7 days.

Visitors to developing countries, like Latin America, Africa, and the Middle East, put themselves at increased risk of TD, according to the United States Centers for Disease Control and Prevention (CDC). TD goes hand in hand with poor sanitation and poor refrigeration, says David N. Taylor, MD, director of the division of communicable diseases and immunology at the Walter Reed Army Institute of Research. Taylor advises travelers to use common sense when determining where and what to eat while abroad. For example, five-star hotels that cater to foreigners are generally safer bets than open-air markets. "If you're going to be eating with locals on the corners in Bangkok, then you're at high-risk," says Taylor, who experienced his worst bout of TD after enjoying a street festival in Peru.

For travelers who do not want to limit their destinations, a healthy dose of awareness can lower their risk of TD. Here are some tips when visiting high-risk locations:

• Do not drink tap water or add ice cubes. Drink only bottled water or, if necessary, local water that you have boiled for 10 minutes or treated with iodine or chlorine. Bottled carbonated beverages, steaming hot tea or coffee, wine, and beer are typically okay to drink.
• Use iodine tablets, such as Potable Aqua, to disinfect tap water.
• Brush your teeth using bottled, boiled, or iodine-treated water only.
• Avoid eating foods from street vendors or unsanitary eating establishments.
• Avoid raw foods, especially salads and fruits (unless you can peel them yourself).
• Avoid cooked food that has been sitting out in the open, even if it is re-heated. Food still hot from an oven is generally safer.
• Avoid seafood from tropical reefs, some of which can be toxic even after cooking.
• Feed children six months and younger breast milk or formula prepared with sterilized water.

In addition, the Infectious Disease Society of America (IDSA) suggests that you avoid these foods:

• Foods that are not steaming hot
• Unpasteurized dairy products
• Cold sauces and toppings
• Open buffets
• Undercooked or incompletely reheated foods
• Fruit juices

It is a good idea to see your doctor to get medicines before you go. Taylor prescribes travelers a supply of antibiotics and advises them to take along anti-diarrheal medicine.

What if you do get sick? At the first sign of diarrhea, Taylor recommends beginning a two- to three-day course of antibiotics, as well as taking anti-diarrheals medicines as needed for more immediate relief.

Taylor cautions against giving anti-diarrheal medicine to young children, though. Young children with diarrhea should see a doctor early on because they are at a higher risk for dehydration than adults. For mild to moderate diarrhea in children, make sure your child is staying hydrated. If diarrhea is severe (10 or more watery stools per day) or the child is urinating less frequently (a sign of dehydration), get medical care right away.

Staying hydrated is an essential part of treatment for adults, as well. Dehydrated travelers can also find relief using oral rehydration salts (ORS), which are widely available in developing countries. However, ORS should not be used as a substitute for safe drinking water.

Seek immediate medical care for TD in any of the following situations:

• Vomiting or diarrhea does not go away after a couple of days
• Symptoms do not subside after 3-7 days and/or after antibiotic treatment
• Dizziness or lightheadedness
• Worsening pain
• High fever and/or disorientation
• Stools are bloody and/or contain mucus
• Signs of dehydration, such as decreased saliva or urination
• Rapid, irregular heartbeat; chest pain
• You are pregnant or caring for a young child who develops diarrhea

In some cases, TD can persist despite antibiotic treatment. Rarely, it can trigger other gastrointestinal problems. See your doctor if symptoms worsen or do not resolve.