Myth #5: It Transmits Diseases

The “Ick” Factor

I’ll admit it—20 years ago, I believed this myth. The thought of using bar soap after someone else, if I believed soap carried germs, gave me that “ick factor.” However, years of learning and research have shown me otherwise.

Think about it: how many people feel uneasy at the idea of sharing bar soap in a public restroom? It’s a rare sight these days, as most restrooms now use liquid soap dispensers. Even hotels still offer those miniature bars, but I don’t use them—I always bring my own soap (“Have Soap, Will Travel,” as a fun nod to Have Gun, Will Travel. Yes, I’m showing my age).

Germs Are Everywhere

Microorganisms are ubiquitous—they’re present everywhere in our environment. This raises an important question: Can bacteria lingering on a used bar of soap transfer to someone else’s hands during use? This question has been studied for decades, and the results consistently indicate that it is not a significant concern.

What Studies Say About Contamination

Researchers have demonstrated that microorganisms can be isolated from used bars of soap (Bannan & Judge, 1965; Litsky & Litsky, 1967; Kabara & Brady, 1984; McBride, 1984). However, only one of these studies–conducted by Bannan and Judge in 1965–specifically examined whether washing with contaminated soap bars could lead to cross-contamination.

In more recent research, a different method was used to test this question. Bars of soap were deliberately contaminated with much higher levels of microorganisms than typically found on used soap. The findings showed that bacteria were not transferred to users’ hands during washing.

The Conclusion

The available evidence indicates that using bar soap—even when contaminated—is unlikely to transfer bacteria to the hands. For those who enjoy diving deeper into research, the full article is available: Heinze JE, Yackovich F. Washing with contaminated bar soap is unlikely to transfer bacteria. Epidemiol Infect. 1988 Aug;101(1):135-42. doi: 10.1017/s0950268800029290. PMID: 3402545; PMCID: PMC2249330.

In summary, bar soap does not appear to facilitate disease transmission. The evidence suggests that the “ick factor” is driven more by perception than by measurable risk.

Read the complete article: Heinze JE, Yackovich F. Washing with contaminated bar soap is unlikely to transfer bacteria. Epidemiol Infect. 1988 Aug;101(1):135-42. doi: 10.1017/s0950268800029290. PMID: 3402545; PMCID: PMC2249330.

For those who prefer a brief overview, a concise summary of the results is available, click here.

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