Fluid replacement with aggressive oral hydration without further treatment is the most appropriate treatment recommendation for this patient with mild travelers' diarrhea. Travelers' diarrhea is defined as the occurrence of three or more unformed stools per day with abdominal pain or cramps, nausea or vomiting, bloody stools, or fever and is the most common travel-related infection. Depending on the geographic region, the incidence of gastrointestinal infection may occur in greater than 30% of travelers. Africa, Asia, South and Central America, and Mexico are considered the regions with the greatest risk. The diarrhea is usually self-limited, lasting 1 to 4 days. Enterotoxigenic and enteroaggregative Escherichia coli are the most common bacterial pathogens. Less often, Salmonella, Shigella, Campylobacter, Aeromonas, Plesiomonas, and noncholera Vibrio species are involved. With the exception of rotavirus and norovirus, travelers' diarrhea caused by viral infections is uncommon; norovirus has been associated with diarrheal disease outbreaks aboard cruise ships. Protozoan pathogens are isolated in less than 10% of cases. However, no definitive microbiologic agent is identified in approximately one third of patients. The use of prophylactic antibiotics is effective in reducing the risk for travelers' diarrhea, but, to avoid potential adverse effects, is generally reserved for patients with a history of inflammatory bowel disease, immunosuppressive illnesses, or chronic diseases that could become more severe or be exacerbated by dehydration brought on with significant diarrhea.

Antibiotics lessen the duration of diarrhea by a few days, but their use is generally limited to patients with more severe disease, usually defined as more than four unformed stools per day with fever and blood, pus, or mucus in the stool. Antibiotic treatment may also be a reasonable option in patients with milder illness if it is markedly disruptive to travel plans.

Antimotility agents, such as loperamide, may relieve symptoms in patients with travelers' diarrhea. However, they do not treat the underlying infection. Concern exists that using antimotility agents alone may prolong dysenteric illnesses without treatment of the underlying infection. For this reason, antimotility agents are generally not recommended without concurrent use of antibiotics for treatment of travelers' diarrhea.