Listerine Won't Cure the Clap

Image via Getty. Sorry by Bobby Finger.
Image via Getty. Sorry by Bobby Finger.

Sexually active people and anyone owning stock in Johnson & Johnson were delighted Tuesday by reports of a new study finding that Listerine treats gonorrhea. Left out of the headlines were helpful details like “gonorrhea killing powers limited to the front of the throat,” “study only looked at very short term benefits,” and “ small sample size.”


The study, published this month in Sexually Transmitted Infections, had two parts—one in vitro (in a petri dish) and one clinical trial (in real people). The first part found that Listerine inhibited the growth of Neisseria gonorrhea over 48 hours. Conclusion: something in Listerine prevented the gonorrhea strain tested from growing. The second part looked at whether that finding holds true in human beings, in this case, 58 men who have sex with men (MSM) who had tested positive for gonorrhea of the throat.

Each man was randomly assigned to gargle either Listerine or saline for one minute (twice as long as suggested by the directions from Listerine). After five minutes, they were tested for gonorrhea with swabs of the posterior oropharynx (the back of your throat) and the tonsillar fossae (the side of your throat where your tonsils live). Researchers found that Listerine effectively reduced the amount of gonorrhea found on the tonsillar fossae but had no significant effect on the infection in the back of the throat. People are rightly excited by this finding because antibiotic resistant strains of gonorrhea are on the rise and the medical community is frantically grasping at straws for any possible alternative treatments.

Both parts of this small study lend credence to Listerine’s original nineteenth century claim that their product could both clean floors and cure the clap. But a few questions linger. For one, the study only looked at cultures taken five minutes after gargling. Do the benefits last long term or is the effect short term? We absolutely can’t say that it “cures” or “treats” gonorrhea because all we know is what happens right after you use it. Lead author Eric Chow, senior research fellow at the Melbourne Sexual Health Center, stressed to Jezebel that they did not use the word cure in their article because the idea “is not supported by any scientific evidence.” More detailed lab work and studies over longer periods of time are needed before you can toss around a word like that.

Dr. Wenyuan Shi, professor and chair of oral biology at UCLA School of Dentistry, said in an email to Jezebel that he bought the study’s results, but urged caution: “With the active ingredients of alcohol and essential oils, the solution has the ability to kill a lot of bacteria. However, it is killing the gonorrhea-associated bacteria in the throat, not the STD gonorrhea.”

In other words, the Listerine was capable of killing bacteria, but not necessarily doing anything about the infection.

The study also did not parse out if there is any difference between the bacteria that were killed off by the Listerine Cool Mint and those that persisted. Are the 57 percent of bacteria that survived the gargling the dreaded super bugs that haunt my dreams (that’s not a joke, antibiotic resistance is terrifying and you should all be constantly afraid)? Or did those bacteria only survive because the participants had poor gargling technique? What is good gargling technique? There are many questions to address in future research on whether antiseptic mouthwashes (including cheap store brands!) can cure gonorrhea of the mouth and throat, but these findings set things off in a promising direction.


This study leaves us a long way from recommending mouthwash as a standard part of sexual health. If swishing around some Listerine after oral sex makes you feel better, it probably won’t hurt, but it will not cure or treat an existing infection—that’s what antibiotics are for. Chow emphasizes that, while the findings are promising, at this point “we do not recommend it at any site and certainly not anywhere other than the throat.” So please don’t douche with Listerine or dip your penis in it. This is most definitely not good for your genitals and will not be an effective way of preventing the spread of infection.

Use condoms instead.

Caroline Weinberg has previously written about science and health at Eater, Vice Motherboard, Aeon, the Washington Post, and a few dry academic publications. You can find her on Twitter @ckw583.


Poey Gordon

So please don’t douche with Listerine or dip your penis in it.

Sigh. I really need to finish reading these articles before I do stuff.