Probiotics containing the yeast strain Saccharomyces boulardii CNCM I-745 may be effective for the prevention of traveler’s diarrhea. A 2019 meta-analysis reported a 21% reduction in the occurrence of traveler’s diarrhea when this probiotic was taken for the duration of the trip.[1] Other strains of probiotics have shown inconsistent results.[1] Preliminary research looking at prebiotic supplementation has found mixed results and more research is needed to understand the potential role of prebiotics.[2]
Bismuth subsalicylate has been found to be safe and effective for the prevention of traveler’s diarrhea when taken for the duration of a trip, up to a maximum of 3 weeks. Protection rates may be as high as 65%.[3]
Bovine colostrum has been researched for the treatment of infectious diarrhea.[4] There is limited evidence that hyperimmune bovine colostrum (HBC), the “first milk” produced by cows that have been immunized against common diarrheal pathogens, may be protective against infectious diarrhea. However, the single clinical trial supporting the efficacy of HBC for the most common traveler’s diarrhea pathogen was funded by a manufacturer of HBC tablets.[5][6]