How do you avoid getting sick while traveling?

The most common travel illness by a wide margin is travelers' diarrhea, affecting a substantial share of visitors to high-risk regions, and it is overwhelmingly transmitted through contaminated food and water rather than air. The practical rules: drink sealed bottled or reliably treated water, skip ice unless you know the water source, avoid raw or undercooked food and unpeeled produce you did not peel yourself, and favor food served hot and freshly cooked over anything sitting at ambient temperature. Street food is not inherently risky and is often safer than a buffet, because high turnover and cooking to order beat food held warm for hours.

Beyond that, a few things carry disproportionate weight. Hand hygiene matters more than any supplement, and hand sanitizer covers the gap where soap and safe water are unavailable. Visit a travel clinic four to six weeks before departure for destination-specific vaccines and, where relevant, malaria prophylaxis, since some require a series or lead time. Check the CDC destination pages, which are specific rather than generic. Pack an oral rehydration solution, because dehydration is what turns an unpleasant illness into a dangerous one, and know that antibiotics are appropriate for some cases and not others. Two frequently ignored items: travel medical insurance, since domestic health coverage often ends at the border and evacuation costs are enormous, and sleep, since the immune effects of severe jet lag and exhaustion are real and compound everything else.