Every few years, it seems there’s a big freakout about how your toothbrush could be speckled with bits of fecal matter courtesy of open-lid toilet flushes. It’s no wonder, really. A poo-covered toothbrush isn’t particularly nice to think about.

Only, your brush may not be disgusting after all, according to results from new research just published in the journal Microbiome.

gif of Elaine saying phew

For the study, researchers asked adults living within a 100 mile radius of Northwestern University to donate their used toothbrushes to science – along with info about their oral care habits, diet, and demographics. Thirty-four brushes were included in the study, from which DNA was extracted and examined to take stock of the bacteria living on them.

The vast majority were kinds that are normally found in the human mouth. They found far fewer that are found exclusively in the gut – and, thus, in feces.

This isn’t to say that finding some of the latter on a toothbrush is impossible – just unlikely.

“It’s reasonably unlikely to find bacteria from our poop on your toothbrush,” Erica Hartmann, an assistant professor of civil and environmental engineering at Northwestern, told Gizmodo via email. “Our findings indicate that you’re much more likely to have microbes from your mouth, or maybe your tap water or plumbing fixtures.”

That said, how you care for and store your brush still matters. Some common behaviors – like storing your brush in a drawer or with its bristles covered – can encourage the growth of all kinds of gunk on your brush. (Remember: The kinds of bacteria that play a role in tooth decay and gum disease absolutely thrive in dark, closed, and damp environments.)

So, a few tips for storing your brush safely:

  • Store your toothbrush away from other brushes and where it can air-dry.
  • Before and after you brush, rinse the bristle head with hot water.
  • Replace your brush every 3 months or whenever the bristles start looking worn.
  • Consider periodically sterilizing your toothbrush. Although there are special devices available that typically use UV light to kill bacteria, they aren’t necessary to get the job done. You can swish the bristle head in an antimicrobial mouthwash, for instance, or a peroxide or baking soda solution (1 teaspoon of 3% peroxide OR 2 teaspoons of baking soda to 1 cup of water). Or you can soak the head overnight in vinegar.

Image by Santeri Viinamäki

Skip to content