Travelers' diarrhea, an acute illness that affects between 20 and 50 percent of travelers to high-risk areas, is usually acquired by eating contaminated food, drinking contaminated water, or coming in contact with the contaminated hands of an infected person. Travelers' diarrhea can be caused by bacterial, viral, and parasitic agents. The Travelers' Diarrhea Consensus Conference has recommended prophylactic measures, which include proper preparation of food and beverages, nonantimicrobial agents, and antimicrobial agents. The newer quinolone antibiotics and bismuth subsalicylate may also be useful prophylactically. Appropriate treatment methods include oral fluids and electrolyte replacement, nonspecific agents such as bismuth subsalicylate, antimotility agents such as loperamide hydrochloride and diphenoxylate hydrochloride, and antimicrobial and antiparasitic agents.