Brief prophylaxis with doxycycline for the prevention of traveler's diarrhea.

A prospective, randomized double-blind trial of doxycycline prophylaxis for traveler's diarrhea was conducted on 145 volunteers during a 2.5-day visit to Mexico. Traveler's diarrhea occurred in 15 (21%) of the placebo group and in 3 (4%) of the doxycycline group (p = 0.002). There was no rebound increase in the incidence of acute diarrhea after departure from the high risk area in the doxycycline-treated group. A variety of bacterial pathogens were isolated from individuals symptomatic with traveler's diarrhea. Nausea alone (8%) or nausea with vomiting (4%) occurred in the doxycycline-treated group only and were the only side effects observed (p = 0.003). We conclude that doxycycline is safe and efficacious for the prophylaxis of traveler's diarrhea for short-term exposure in a high risk area.