Measures that may decrease the risk of TD include Drinking and brushing teeth with bottled, filtered, boiled, or chlorinated water Avoiding ice Eating freshly prepared foods only if they have been heated to steaming temperatures Eating only fruits and vegetables that travelers peel or shell themselves Avoiding food from street vendors Washing hands frequently Avoiding all foods likely to have been exposed to flies Prophylactic antibiotics are effective in preventing diarrhea, but because of concerns about adverse effects and development of resistance, they should probably be reserved for immunocompromised patients.