A gynecologist and an anal surgeon told us we’ve been washing our underwear wrong…

Most everyone (hopefully) knows that putting on a pair of clean underwear should be as much of a part of your daily routine as brushing your teeth and washing your face. But apparently, what constitutes “clean” isn’t quite as simple as you might think. Because as it turns out, tossing your favorite pair of panties into the washer on cold with your other colorful laundry may not be keeping them fresh… and that can be bad news for your anal and vaginal health.

There are a lot of different things that can accumulate down there over the course of a day—dirt, urine, feces, and vaginal discharge, to name a few particularly fun ones—and because the environment between your legs is moist, it’s a breeding ground for bacteria, yeast, and fungi. All of this can lead to infections, which as we all know, are not fun for anyone.

“If you wear dirty underwear, you’re increasing your chances of both fungal jock itch and bacterial dermatitis, which are literal pains in the ass and more prevalent than you’d think,” says anal surgeon and founder of Future Method Evan Goldstein, DO. Lucky Sekhon, MD, a fertility specialist and board certified OBGYN from New York City, adds that you’re also at risk for genital infections. Because of this, you should be changing your undies at least once a day (or more if you work out in them because: sweat), and using best practices to keep ’em clean.

Studies have shown that bacteria can survive a laundry cycle, so pros suggest taking extra measures to make sure it’s fully dead and gone before your next wear. “Underwear, sports clothing, towels, and sheets may need an extra boost of cleaning power by washing in warm water—which is 80 degrees Fahrenheit or higher—with the appropriate dose of a high-quality laundry detergent,” says Tide & Downy principal scientist Mary Johnson. To be extra sure you’re getting all of that infection-causing nastiness out, she suggests spraying your undies with an antibacterial laundry spray like Tide Antibacterial Fabric Spray  ($6) before washing, which will help kill that lingering bacteria.

“If your underwear is white, you can use a little bleach to kill bacteria,” says Dr. Sekhton. “You can also iron your underwear after washing it to further sterilize it.”

In addition to giving your undies a good wash, Dr. Goldstein also touts the importance of refreshing your collection on the reg—ideally every three to six months (…whoops). “Over time, the fabric and its technology will degrade, becoming less and less effective, and it will lose its original fit and shape,” he says. Or, ya know, you can always just go au natural and let it all hang out… as long as you’re changing your pantsleggings and washing them in hot water on the reg, that is.