Some 20%-50% of international travelers develop diarrhea, including me. It can really ruin a vacation. As I’ve dealt with it all my life, I have come up with the best way to prevent it — for me. I offer it here not as medical advice, but in hopes that my experience may help make your travel safer and more enjoyable.

One website you may want to check out is from the US Centers for Disease Control and Prevention. According to them, several studies have shown that bismuth subsalicylate (such as Pepto-Bismol) taken as either 2
tablets 4 times daily or 2 fluid ounces 4 times daily reduces the
incidence of travelers’ diarrhea. At times this has worked for me. But I have to admit, the majority of time it did not work.

Furthermore, they say some antibiotics administered in a once-a-day dose are 90% effective at preventing travelers’ diarrhea. This normally does work for me. I take 100mg of doxycycline per day starting about one day before I travel, up until a couple days after my return. More info on doxycycline here.

In addition, I take a product from Merk called Perenterol. It’s non-pathogenic yeast, saccharomyces boulardii, that is recognized to have
probiotic effectiveness. I recognize it for saving myself many hours in the bathroom! I found a good info sheet on this drug you may want to read. It warns you not to drink alcohol when taking this, as it kills the yeast. Other name brands of this yeast are: Jarrow, Biocodex and Thiemann. I take one pill (200mg) twice a day for three days starting 2 days before I travel. I also take an additional three days at 2 pills per day at the end of my trip staring about one day before I head back home.

Again, I can’t provide you with medical advice legally. I’m just sharing with you what works for me. Check with your doctor before self-medicating.

Here in Costa Rica, all of the above are available over-the-counter and are not expensive at all. Remember, prevention is good medicine!