Ewww! Kissing is Gross - Crozer-Keystone Health System - PA

Published on February 13, 2015

Ewww! Kissing is Gross

Ewww! Kissing is Gross

Couples trade nearly 80 million bacteria
in a single, 10-second “intimate” kiss.

On Valentine’s Day, you might invest in some flowers, chocolates and gifts for your significant other to remind them how you feel about them. You might also kiss them.

It has been a long time since you probably believed you could catch cooties from someone, but a new study may be reinforcing that childhood idea.

While you can’t actually catch cooties from kissing someone, you can swap a serious amount of germs and bacteria. To be precise, the study found that couples traded nearly 80 million bacteria in a single, 10-second “intimate” kiss. And that number soars if a couple kisses more than once a day.


Scientists report that the mouth is home to at least 700 different kinds of bacteria. The research in the study found that the more couples kissed, or at least nine times a day, the more likely they were to have similar bacteria in their saliva. Researchers also found that tongue germs were more similar among couples compared to people who don't know each other.

Of course, with all of that bacteria transferring from one person to another, there’s the chance some not-so-nice germs can be in the mix. So there’s a chance that kissing someone who is sick will make you sick too.

Sicknesses are spread from inhaling infected droplets in the air after a sick person coughs or sneezes, touching a contaminated surface and then touching your eyes or nose and, of course, kissing.

It doesn’t help that Valentine’s Day falls right in the thick of cold and flu season.

But before you ban kissing and start giving your partner reason to worry that you’re headed toward a breakup, you should know that all of that exchanging of bacteria may not always be a bad thing.

That’s because transferring bacteria while kissing your loved one could actually be beneficial to both of your health. Several studies have shown that it’s a good thing to have the diversity in bacteria increase, meaning there’s more variety of species.

While it sounds disgusting that there are more than 700 types of bacteria in your mouth, mouth germs only play a small role because your body houses more than 100 trillion microorganisms, which can help with such things as fighting disease and digesting food.

Kissing, swapping bacteria, and increasing the variety of microorganisms can act as a form of immunization by helping you build up a tolerance. Most doctors will say the bacteria in your mouth isn’t dangerous and it can improve your immune system, unless you or your significant other has a lot of cavities.

So what does all of this mean? Unless you or your loved one is clearly ill, keep kissing! Don’t miss out on a good kiss, especially on Valentine’s Day, because you’re afraid of germs…or cooties.

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