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If something has a benefit, and no harms, then you should likely use it. But if something has no benefits, and potentially real harms, then you shouldn't. The latter is the case with antibacterial soap. Although the stuff is ubiquitous, there's tons of data showing it doesn't do what it's supposed to, while possibly damaging us and the environment. Watch this week's episode to learn about the difference between efficacy and effectiveness, why bacterial counts really don't matter here, and why the FDA made the right call. Then, as always, feel free to attack Aaron in comments or on Twitter.

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John Green -- Executive Producer
Stan Muller -- Director, Producer
Aaron Carroll -- Writer
Mark Olsen - Graphics
Whenever anyone asks me about a health related decision, my answer’s always the same.  Weigh the benefits against the harms.  If there are tons of benefits and almost no harms, you should likely do it.  If there are some benefits and some harms, then it’s a harder choice.  If however, there are almost no benefits and harms, then it’s a no-brainer.  Don’t do it.  But more often than you'd think, we’re doing stuff in that last category.  A recent example is the use of antibacterial soaps.  That’s the topic of this week's Healthcare Triage.


Let’s start with the benefits.  People use antibacterial soaps because they think they’ll prevent more disease and make them healthier.  Is this true?  To the research!

In 2007 a nice systematic review was published in the Journal of Clinical Infectious Diseases, that looked at all studies that were published in the medical literature published between 1980 and 2006.  Twenty seven of them met the criteria for this review.  Four of them were community based randomized control trials.  These studies included children, and they all had outcomes we should care about, like cough, fever, diarrhea and skin infections.  And, wait for it, the use of antibacterial soap did nothing to prevent anyone from getting these illnesses above the use of plain old soap.

This is what we call effectiveness, which is a term that describes how well things work in the real world.  Nine other studies looked at efficacy, which is a term that’s used to describe how well things work in ideal conditions like the lab.

These studies measured how many bacteria were on people’s hands, both before and after using antibacterial soap or plain old soap.  Some of them, not all, did find that bacterial counts were reduced with antibacterial soap.  All of them studied soaps with higher antibacterial content than is normally available.  Some of them required participants to wash their hands multiple times.  A couple required them to wash their hands for at least 30 seconds, and one found that the reduction of bacteria was only seen after getting people to wash their hands 18 times a day, for 30 seconds each, for five consecutive days.  No one does that.

The antibacterial industry will dispute this.  They sometimes point to a metanalysis published in the Journal of Food Protection in 2011.  They found 25 different studies which had a whopping 374 observations included in them.  Can you tell I’m unimpressed?  Most of these studies  had fewer than 15 participants.  The outcome in them was again, the number of bacterial colonies on people’s hands.

You have to remember that here in the real world most communicable diseases are due to viruses, not bacteria.  So all this laboratory focus on bacteria count seems beside the point.  And out here in the real world, it turns out that antibacterial soaps don’t prevent you from getting disease or keep you healthy.  So overall, no real benefits.

Now let’s look at the harms.  That 2007 systematic review found 11 studies examining how antibacterial soaps affect an emerging resistance in bacteria.  In the lab, they found that the use of these soaps did appear to increase the number of antibiotic resistant bacteria found.  Unfortunately though these studies appear to be underpowered, the trends did look worrisome.  Even the possibility that we’re creating resistance is a problem though.  We can’t conclusively say that it’s happening because of these studies but it’s such an issue that you need a really, really good reason to risk it.

There are animal studies that show the risks of antibacterial ingredients interfering with the endocrine system.  None in humans though.  But there are studies in humans that have found an association between the use of  antibacterial ingredients and allergies and hay fever.  This stuff gets into our water, and horrifyingly into animals in the water too.  

So what we have here is almost no evidence that things do what they’re supposed to, prevent communicable illnesses.  We have some evidence or at least concerns, that they do harm.  When something has no benefit and even potential harm, you don’t do it.  That’s what’s going on here.  That’s why the FDA recently moved to change its policy to require manufacturers to prove that antibacterial components work and are safe, if they want to keep using them.  That’s not likely to occur.  As a side note, the FDA first proposed removing antibacterial components in 1978.  It only took them this long to act on it.  

This isn’t to say that good hand hygiene isn’t important.  A systematic review published in the American Journal of Public Health found that teaching people about hand hygiene and getting them to wash their hands, significantly reduced the risks of getting a gastrointestinal or respiratory illness.  Hand washing works.  They also found that using antibacterial soap didn’t do much at all above plain old soap.  Antibacterial soaps, no benefit, potential or real harm.  No-brainer. Stop using them.

This episode of Healthcare Triage  is supported by, a leading provider of premium digital spoken audio information and entertainment on the internet. allows the users to choose the audio versions of their favorite books, with a library of over 150,000 titles.  We recommend, “Everything Bad is Good for You” by Steven Johnson.  It fits very well with our episode on how the sky isn’t falling.  You can download a free audio version of “Everything Bad is Good for You” or another of your choice at