Spit might pose some surprising risks.

By Gabrielle Kassel
June 24, 2019

So you're easing into a sex session with your partner and even though you're totally up for it, things are a little dry down below. (Hey, it happens.) You don't have any lubricant on hand, so you work up a little spit and use it as your makeshift lube. Or you have your partner go down on you and use their saliva as a substitute when it's time for penetration.

Not a big deal, right? Actually, spit just might be dangerous. “When they don’t have lube on hand, I’ve had patients tell me that they use saliva,” Felice Gersh, MD, author of PCOS SOS: A Gynecologist’s Lifeline to Naturally Restore Your Rhythms, Hormones, and Happiness, tells Health.

Saliva may seem like a harmless swap for your own natural lubrication or the store-bought kind—it's always available and free, after all. But your vagina will thank you for not resorting to it for three important reasons.

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STIs can be spread through saliva

“Any STI in the throat or mouth can be transmitted to the genitals through saliva,” explains Dr. Gersh. In other words, if your partner has an active herpes lesion for example, using their spit to make things slick could leave you with genital herpes.

This scenario happens more than you might think—and it's the most common way genital herpes is contracted, she says. Even if you don't see a cold sore on or around their mouth, the virus can still be transmissible. “Herpes can present with blisters or sores, but it can also present asymptomatically,” she explains.

Herpes isn’t the only oral STI you could contract. “Gonorrhea, chlamydia, HPV, syphilis, and trichomoniasis can also all be transmitted to the genitals through saliva,” adds Dr. Gersh. And like herpes, these infections may not have any symptoms.

You can get a vaginal infection

“The bacteria in saliva are very different than the bacteria in your vagina,” says Dr. Gersh. Saliva also contains digestive enzymes that break down food. When you introduce these bacteria and enzymes into your vagina, the result can upset your vaginal microbiome and leave you susceptible to developing a yeast infection or bacterial vaginosis, she explains.

Both of these annoying yet curable infections develop when the balance of yeast and bacteria that naturally exist in the vagina is thrown off. “Using saliva as lube provides a perfect storm to alter the vaginal ecosystem enough to trigger one of these infections," says Dr. Gersh.

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Spit just isn't as good as lube

Even if you remove the risk of contracting an STI or vaginal infection, spit is still not advised. “It has no innate qualities that would make it a good lubricant," says Dr. Gersh. "It doesn’t have the slippery consistency, it evaporates and dries more quickly, and further, it’s irritating.”

Personal lubricants on the other hand, are designed to create slickness that's very similar to the lubrication your own body produces. “Lubricity creates a glidey feel, which helps to decrease friction,” she says. Friction can cause small nicks or tears in the vagina, which besides being painful might allow harmful microbes into the body—something you definitely don't want.

The bottom line? “99.9% of people have probably used spit as lube with a partner at some point, but it is not the best or safest choice,” advises Dr. Gersh. Consider that a reason to stock up on a water- or silicone-based personal lubricant so you'll have some whenever the mood strikes.

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