A 2021 systematic review and meta-analysis of bismuth subsalicylate (BSS) studies related to diarrhea, mostly unpublished manufacturer-sponsored, was undertaken. Though generally I am extremely critical of manufacturer-sponsored literature, particularly if it has never undergone some kind of peer-reviewed process, the results of this review are consistent with other non-sponsored peer-reviewed studies on the same topic.
Literature supports that bacteria exposed to BSS results in loss of cell membrane integrity and possible inactivation of ATP leading to organism death. There are also in-vitro antimicrobial effects. Viral inhibition has also been shown with BSS. Specifically, replication of rotavirus, a common cause of infectious diarrhea, is significantly reduced in the presence of BSS. Additionally, BSS decreases GI motility, which can help relieve symptoms.
Manufacturer-sponsored placebo-controlled trials involving 404 subjects, 16 to 70 years old, pretreated with BSS for up to 21 days, started 1 day before or 2 days after travel to Mexico or Africa (2.1 to 4.2 grams total daily dose of BSS), showed self-assessed traveler’s diarrhea was 3.5X less in those on BSS prophylaxis.
Manufacturer-sponsored studies of 840 subjects, receiving 2.1 to 4.2 grams total daily dose of BSS for treatment of diarrhea of any cause, showed a 3.7X reduction if treated with BSS for only 1 to 2 days. This was based on a physician’s or the patient’s assessment. When the authors looked at just infectious diarrhea, reduction was 3.1X. Additionally, stool cultures after 1 to 2 days of BSS treatment didn’t show any significant gut biome changes.
There is also a CDC study of BSS versus placebo treatment for diarrhea in Pakistan, which showed a 45% reduction in need for antibiotics if treated with BSS.
Full disclosure: there is a recent study which didn’t show any benefit to BSS prophylaxis in traveler’s diarrhea, but that study was limited by very few travelers actually experiencing traveler’s diarrhea, regardless of BSS or placebo.
BSS is a potentially useful over-the-counter medication to have available when traveling, for the inevitable diarrhea that so often happens with travel to low-resource settings. I have used this technique successfully in Africa and Afghanistan.
Check with your own medical provider to ensure this is a viable medication for you, based on your own health history and routine medication use.
Brum JM, Gibb RD, Ramsey DL, Balan G, Yacyshyn BR. Systematic Review and Meta-Analyses Assessment of the Clinical Efficacy of Bismuth Subsalicylate for Prevention and Treatment of Infectious Diarrhea. Dig Dis Sci. 2021 Jul;66(7):2323-2335.
