The prevention of traveller's diarrhea should be limited to the evaluation of drinking water, the avoidance of certain foods and careful hygiene of the hands. Although their efficacy is somewhat controversial in this context, these precautions at any event reduce the risk of acquiring other feco-orally transmitted diseases. Because of the increasing resistance of the bacteria responsible and their multiplicity, early treatment of any actual case of traveller's diarrhea is preferable to prophylactic antibiotics. Therapeutic indications vary according to the severity of traveller's diarrhea and the general condition of the patient. Travellers must be aware of these considerations before their departure.