It’s one of the most important tools in personal hygiene: your toothbrush. And yet the thing you rely on to keep your teeth clean may be covered in something that will make you gag: fecal matter.

A new study has found that toothbrushes in shared bathed bathrooms are more likely to have traces of poop on them, and that can lead to the spread of disease, according to a UPI report.

Scientists at Quinnipiac University in Connecticut examined toothbrushes from students in a bathroom that at least nine people shared, and they found that a whopping 60 percent of them had some fecal matter on them, no matter how carefully they were kept from the open air.

Even if you are the only user of the toilet in your bathroom, you’re probably still going to find fecal matter on your toothbrush. But at least it’s your own, and therefore it’s not going to spread any disease.

However, in the case of those in communal bathrooms, 80 percent of contaminated toothbrushes had someone else’s poop on them, and that can create a risk of spreading bacteria, viruses, or even parasites, said Lauren Aber, the lead study author, according to the report.

What can you do about it? Not much as far as daily protection, but generally you should follow the American Dental Association’s advice and not share toothbrushes, also rinsing them both before and after you use them, and avoid storing them closely to other toothbrushes. And don’t put them in a container — that’s actually worse because it creates a moist area where bacteria can grow.