The Final Word on What You Can Catch From Oral Sex

The internet is a breeding ground for medical misinformation. Articles sneakily pop up—and often go viral—with under-researched findings, overstated claims, and pseudoscience about what foods to eat to prevent STIs. We look into every homemade "cure" we can think of, hoping that something will work. Once in a while, something that actually has some science behind it surfaces. Remember the claim about Listerine's supposed gonorrhea-killing powers that circulated everyone's feed back in December?

In a small study (which included 60 gay and bisexual men with pharyngeal gonorrhea), scientists at the Melbourne Sexual Health Centre found that one minute of gargling the mouthwash was enough to reduce gonorrhea bacteria by nearly half. But does this mean we can all just mouth-douche away our potential STIs? In short, no. STIs are complicated and it's much better practice to work on prevention rather than scrambling at the last minute to protect yourself.

"I'm afraid that STI prevention from oral sex is much less exciting and full of home remedies than people might hope for," says Debby Herbenick, associate professor at Indiana University School of Public Health and author of Sex Made Easy. "I have heard about the anecdotal Listerine information, however, empirical research is needed before this can be recommended."

That's not the only place where empirical research is lacking, either: We don't have data on the rates of the most common orally contracted STIs due to the limitations of how the data is collected, according to a CDC spokesperson. Labs and providers are only required to report a positive test result, but not what body part the sample was collected from. So what can you catch from oral sex and how can you treat it?

"Many STDs can be spread through oral sex," the CDC spokesperson tells me. "However, it's difficult to compare the exact risks of getting specific STDs from specific types of sexual activity. This is partly because most people who have oral sex also have vaginal or anal sex." At least we're mixing it up?

Most STIs can be transmitted orally, though some are more likely than others, Herbenick says. "For example, gonorrhea, syphilis, and herpes are more easily transmitted orally than HIV, although HIV can also be transmitted orally. Condom use during oral sex can reduce the risk of STIs, though there's still some risk of STIs in areas not covered by the condom—for example, syphilis or herpes, which may have lesions present outside the condom-protected area."

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When asked what STIs could not be transmitted via oral sex, however, both Herbenick and the CDC refrained from commenting. Peter Leone, a professor of medicine at the University of North Carolina's School of Medicine, says there's only one STD—trichomoniasis—that he's never heard of being orally acquired or transmitted. "That's probably it of the most common STDs," he says, adding that HIV can possibly be acquired orally, but it's not easily acquired that way.

"Generally speaking, we'd view it [HIV] as not orally transmitted without a lot of caveats," he says. "In other words, someone who has a lot of oral lesions, or bleeding where they might come into contact with someone else who might have HIV." In terms of what we commonly think of as STIs, he says, herpes, gonorrhea, chlamydia, HPV, and syphilis can all be transmitted orally.

Leone says the CDC's evidence-based approach is part of why they're more reluctant than, say, a group of respected doctors to weigh in on the subject. "Until they get a large number of studies done with statistical significance, they won't make recommendations. The problem is the data lag."

As for what you can do to stay safe, Herbenick sticks to classic recommendations: Ask your partner for their STI status, get tested together, and let your healthcare provider know about the kinds of sex you engage in—oral, vaginal, anal, sharing sex toys—so they can assess your risk and offer you the appropriate testing. Limit your number of sexual partners, too, and get treated if you have an STI. And—we'll emphasize this again—wear a condom. That last point, Leone concedes, tends to face the strongest opposition. Lots of men simply don't like wearing condoms. "It's a tough thing," he says. "We need to come up with better methods. I think the dirty little secret is that we talk about barrier methods, but most people don't like the way condoms taste or feel, and even flavored condoms aren't like 'wow, that's a great flavor, think I'll do that again.'"

It doesn't help that porn has been equally slow on the uptake. While porn sex isn't necessarily reflective of sex in real life, the widespread lack of condoms is part of the fantasy. On the other hand, it's worth noting that the reason porn actors can ride bareback is due to the industry's vigorous STI screening procedures—performers provide their employers with constant STI reports and stay on top of their health to better protect each other.

"The adult entertainment industry has been self-imposing strict testing protocols since 1998, when all active performers were required to have a clean bill of health from within 30 days prior to any shoot they worked on," says Lynsey G, author of Watching Porn: And Other Confessions of an Adult Entertainment Journalist. Over the years, as testing technology changed, and that window has been reduced to just 14 days, she says. The 14-day window corresponds to the Aptima HIV-1 RNA test that industry-approved clinics use, which detects any trace of HIV in the bloodstream within 14 days of exposure. Most industry testing panels also including screenings for Hepatitis B and C, trichomoniasis, syphilis, chlamydia, and gonorrhea.

Choosing to forego safer sex methods leaves the door wide open to STIs. It might be slightly inconvenient to run to the other room for a condom, but it's a lot easier than running to the clinic to have your throat swabbed, or picking up an antibiotic prescription that requires you to avoid alcohol and sex for two weeks. Not to mention the awkward "so BTW, I have chlamydia" text to follow. And that's one of the better-case scenarios of catching an oral STI.

But if you're adamant about not licking latex, let's at least revisit that Listerine claim. Believe it or not, it's actually based on good data, Leone says. (Granted, it's one study.) "It makes some sense that you're using an antiseptic to try to reduce the burden. Would I depend on that alone? No," he says. "It's not going to get rid of every damn virus that could be in your throat. I would still recommend people go in and get screened."

So while home remedies may sound appealing, they'll never be as reliable as using barriers and getting tested. Stay cautious—and stay strapped.

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