Is This a Kissing Blog?

wide the-princess-bride-kiss

Buttercup and Westley’s final kiss in Rob Reiner’s 1987 adaptation of William Goldman’s classic, The Princess Bride

“Since the invention of the kiss, there have only been five kisses that were rated the most passionate, the most pure. This one left them all behind.” –The Princess Bride

Ah, wuv. Twue wuv. With that record-shattering kiss, Buttercup and Westley traded vows of everlasting love, the promise of a lifetime’s “As you wish”es, and approximately 80 million bacteria.


Yes, a research group at TMO in the Netherlands investigated how kissing affects a couple’s oral bacteria and found that Valentines swap more than just spit. Just like in your intestines, stomach and skin, your mouth and airways are home to a whole host of bacteria that help keep you healthy, known as your microflora.

Oral bacteria were almost certainly the first to be viewed by humans when back in 1683, Antonie van Leeuwenhoek (the father of microbiology) scraped some tarter off his own teeth and stuck it under a microscope. As many as 600 different species of bacteria can be found in the human mouth, some of which are responsible for common problems like gum disease and tooth decay. However, keeping the bacteria living in your mouth happy and balanced helps keep out disease-causing bacteria, stops bad breath, and may even help prevent more serious diseases elsewhere in your body, including stroke, cardiovascular disease, and diabetes.

While the makeup of a person’s microflora is important, it isn’t static. The mouth is an open system, meaning that the composition of the bacteria living there can be changed by things like your genes, age, diet and who you…interact with.

princess bride grandson

INTIMATE kissing? Are you trying to kill me?


The Dutch research group that performed this study swabbed the mouths of random visitors at the Artis Royal Zoo in Amsterdam. Then, the researchers had them make out for ten seconds before re-sampling. You can’t make this stuff up.

The researchers found that among their amorous zoo-goers, romantic partners had more similar oral microflora composition pre-kiss than two people not in a relationship. In particular, partners showed the most striking similarities in the microflora associated with their tongue. The long-term couples’ microflora didn’t change much post-kiss, but this is most likely because they are in like with each other and already swap bacteria fairly regularly.


The scientists conducting the study then wanted to know precisely how many bacteria are passed around per make-out sesh. To answer that question, they gave one partner of each couple probiotic yogurt containing what they referred to as “marker bacteria” and, again, had them snog away.

They then resampled everyone’s mouths to see how much bacteria had transferred from the person who ate the yogurt to the person who did not. It turns out that on average, 80 million bacteria were swapped from one mouth to the other per 10-second make-out.

aaaaaas youuuuu wiiiiiiiiiish

Aaaaaaaaassss youuuuuuuuu wiiiiiiiiiish!


True love is not as easy as one simple kiss, however; it requires effort and real commitment. In fact, the researchers found that in order for a couples’ microfloras to really change to resemble each other, they need to kiss — intimate kissing, they specified — nine times per day.

So, friends, to have the sort of love that cannot be tracked, even with a thousand bloodhounds, that cannot be broken, even with a thousand swords, that is second only to a good MLT — remember to say those three little words every time your Valentine wants a smooch: As you wish.