Many cases of traveler's diarrhea can be prevented. Keep the following rules in mind, even in expensive resorts and hotels.
Alcohol does not sterilize water, so be cautious about contaminated water (including ice) used in mixed drinks.
Carbonated beverages and bottled water are usually safe to drink, but don't use ice, which could be contaminated. Drink from the bottle with a straw, rather than out of a glass. The glass may have been washed with contaminated water.
Purify water by boiling it for at least five minutes or using a water purification system.
Hot coffee and tea usually are safe to drink because the water has been boiled.
Don't eat fruits and vegetables unless they can be peeled, and you peel them yourself (to make sure that they are not contaminated after they are peeled)
Avoid dairy products, unless you are sure they have been pasteurized, and avoid undercooked meat and fish.
Wash your hands with the cleanest water available, or disinfect them with alcohol wipes before eating.
You can decrease your chance of getting diarrhea by taking two tablets of bismuth subsalicylate (Pepto-Bismol) four times a day, although you shouldn't do this for more than three weeks. Common side effects of bismuth subsalicylate include black stools and a temporary black discoloration of your tongue. If you develop ringing in the ears, stop the medication; you may be developing salicylate toxicity. Aspirin and bismuth subsalicylate contain the same active ingredient, so don't use aspirin while you take bismuth subsalicylate. If you are allergic to aspirin, are pregnant, or have a history of kidney disease, ulcers or other bleeding disorders, consult your doctor before taking bismuth subsalicylate.
Do not take antibiotics to prevent diarrhea unless your doctor tells you to. Antibiotics can have side effects, including sensitivity to sun, allergic reactions and vaginal yeast infections. Antibiotic treatment may be prescribed for people with certain medical conditions. For them, a bout of diarrhea could be dangerous.