Is it really true that you can pick up diseases simply from having the bottoms of your bare feet come in contact with germs?

Or is the flip-flop admonition one you can safely ignore?

We knew exactly whom to call for answers—“Dr. Germ,” aka Charles Gerba, PhD, a professor of environmental microbiology at The University of Arizona in Tucson, who is widely known for his research on bacteria and other organisms covering public surfaces. What Dr. Gerba told us about locker rooms and showers…


First, Dr. Gerba explained what’s really on public shower floors since, frankly, it isn’t just water that’s swirling down the drain. Sweat and skin cells are definitely in the mix, he said, and some people (though we hope not many) urinate in the shower as well, whether accidentally or on purpose. Along with all that, he said, are various strains of mold, algae and fungi that either grow in moist environments or are carried there on people’s bare feet.

Also, when you consider that people coming in from the outdoors wear their street shoes right into the locker room, and the locker room leads to the shower…well, you can assume that outdoor contaminants are making their way onto the public shower floor, too. Those contaminants might include dog feces…human sputum…pesticides…E. coli bacteria…coliform bacteria…ringworm…we could go on.

True, the floors in public showers and locker rooms usually are cleaned with strong detergents that eliminate most germs—but how frequently and thoroughly they are cleaned can vary greatly from establishment to establishment.


If you have an open sore on your foot and you step on a germy floor, pathogens may indeed enter your body and cause infection. You’re also at increased risk if you’re allergic to molds, since those thrive in damp environments. Otherwise, Dr. Gerba said, the chances are pretty slim that you’d get an infection from walking barefoot on surfaces that harbor pathogens such as those listed above—so that’s good news.

However, one germ that can exist in public showers truly is worth worrying about—the fungus that causes tinea pedis, better known as athlete’s foot. This infection can be transferred very easily from one person’s feet to a shower floor and then from the floor to someone else’s feet—even if that second person has no open sores on his or her feet. Though athlete’s foot is not life-threatening, the cracked, itchy skin that it causes between toes can make you miserable—so it’s an infection you definitely want to avoid.

For that reason, Dr. Gerba agreed that the old warning about public showers is true—it is a good idea to wear flip-flops or other waterproof sandals in a public shower or locker room. So the next time you’re tempted to bare it all at the gym, look down—and make sure that at least your feet are covered. Also follow these tips to keep your feet germ-free…

  • After showering, dry your feet thoroughly—including between your toes—with a clean towel to help prevent athlete’s foot.
  • If you have had athlete’s foot in the past, you clearly are susceptible to it—so consider applying an antifungal foot powder before you put your shoes back on.
  • Even when you’re not showering at the gym but are just getting in and out of your sneakers, sit on a bench and keep your bare feet in the air so they don’t touch the floor. Better safe than sorry!