Mouthwash May Treat Pharyngeal Gonorrheae

A new study published in Sexually Transmitted Infections used an in vitro trial and randomized control trial of men who had sex with men to test the effects of Listerine on Neisseria gonorrhoeae cultures in men who had sex with men. Their findings showed that Listerine significantly reduced the number of cultures in both trials and may be an effective preventative for the spread of gonorrhea.

In the in vitro trial, researchers used two Listerine products containing 21.6% alcohol and phosphate buffered saline as a control. Researchers created a standard suspension of ~108 colony forming units per mL of Neisseria gonorrhoeae and added it to 1:2 to 1:32 dilutions of both mouthwashes for 1 minute. The experiment was replicated 3 times, and cultures of the Neisseria gonorrhoeae were recorded.
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The randomized control trial used 196 men who had sex with men, 104 received Listerine, and 92 received saline. Prior to using the solution, 28 men tested positive for gonorrhea cultures at both the posterior oropharynx and tonsillar fossae, 15 were positive at the posterior oropharynx only and 15 were positive at the tonsillar fossae only, with a total of 58 men testing positive for Neisseria gonorrhoeae cultures. The men gargled the Listerine or saline for 1 minute and were swabbed 5 minutes afterward.

Researchers found that the use of Listerine solutions for the in vitro experiment significantly reduced the number of Neisseria gonorrhoeae cultures, but the phosphate buffered saline had no effect. Likewise, 52% of the men who tested positive with gonorrhea cultures on the pharyngeal surface did not test positive after using Listerine compared to 84% of men in the saline group who still tested positive for Neisseria gonorrhoeae.

According to the researchers, Listerine may be an effective means of preventing and treating Neisseria gonorrhoeae in men who have sex with men. It is cost effective, easily accessible, and has the possibility of decreasing Neisseria gonorrhoeae cultures if used over time.

—Melissa Weiss


Chow EPF, Howden BP, Walker S, et al. Antiseptic mouthwash against pharyngeal Neisseria gonorrhoeae: a randomized controlled trail and in vitro study [published online December 20, 2016]. Sexually Transmitted Infections. doi:10.1136/sextrans-2016-052753.