For the same reasons you wouldn’t share a fork with a stranger or, say, lick an ATM, inserting your tongue into someone else’s mouth can set your body up for disaster. Here’s how:
1. IT CAN EXPOSE YOU TO NASTY BACTERIA THAT MAKE YOU FEEL MISERABLE.
“Mouths can serve as a transmission route for germs because there is close connection with the gastrointestinal and respiratory systems, and these are common sites of infections for germs,” explains Kelly Reynolds, PhD, a microbiologist at the University of Arizona’s Zuckerman College of Public Health. And that goes for people who seem perfectly healthy, since humans can shed pathogens through saliva for a few days before and after experiencing symptoms.
As you might imagine, open-mouthed kissing is particularly icky: It transfers more germs than closed-mouth kissing, and the more germs you’re exposed to, the more likely you are to get sick, according to Reynolds.