STIs can be some of the most painful and embarrassing infections to get. Although they're a health nuisance, they're treatable for the most part — except for antibiotic resistant "super gonorrhea." Now, researchers at Melbourne Sexual Health Center in Australia suggest Listerine mouthwash could become a gonorrhea treatment.

"With daily use it may increase gonococcal clearance and have important implications for prevention strategies," wrote Eric P. F. Chow, from Melbourne Sexual Health Centre in Australia, and colleagues, in the study published in Sexually Transmitted Infections.

Read More: Antibiotic Resistance Leads To 'Super Gonorrhea'

In the U.S., gonorrhea is one of the most common STIs, where more than 800,000 infections occur each year. Some men and women may report symptoms, like discharge or burning when urinating, but most people infected with gonorrhea do not. This means many infections go undetected and untreated. It also increases a person’s risk of contracting and transmitting HIV.

Gonorrhea rates have significantly increased, up 13 percent from 2014. The rise in the gonorrhea rates during 2014–2015 was seen among both males and females; however, the increase was larger among males. A data analysis found 120 out of every 100,000 men had gonorrhea, while only 101 women per 100,000 tested positive for it.

Currently, the Centers for Disease Control and Prevention recommends only one first-line treatment regimen: injectable ceftriaxone, in combination with one of two other oral antibiotics, either azithromycin or doxycycline. This regimen remains highly effective in treating gonorrhea and causes limited side effects.

Medication could be costly, but Chow and his colleagues found Listerine could be a easier, cheaper, and more accessible way to treat the STI than standard antibiotics. Out of 58 men with gonorrhea of the throat, those who gargled with Listerine, and got swabbed for gonorrhea, tested only 52 percent positive, compared to the 84 percent who tested positive after the saline solution. Moreover, the mouthwash served as a preventative measure; those who used Listerine had 80 percent lower odds of testing positive than the men who gargled with saline solution.

A total of 58 gay and bisexual men who tested positive for gonorrhea in their throats were included in the study. They were asked to gargle for one minute with either 20 milliliters of normal Listerine or with saline solution. The men were re-swabbed five minutes after gargling.

Prior to testing on men, the researchers applied dilutions up to 1:32 of Listerine Cool Mint and Total Care with 21.6 percent alcohol to cultures of N gonorrhoeae to see which, if any, of them might inhibit bacteria growth in a petri dish. They also applied a saline solution to an identical set of cultures. A notable decrease in gonorrhea bacteria was spotted.

Read More: Experimental Gonorrhea Treatment May Cure Antibiotic-Resistant Disease

Listerine had a moderate effect on the amount of viable gonorrhea in the throat, but researchers aren't sure how long these results will last, or how long men would have to gargle and rinse with mouthwash to prevent future gonorrhea infections in the throat. However, the laboratory test results suggest a longer-term effect, they reason. Moreover, it's unclear what effect Listerine would have on gonorrhea transmission to parts of the body, like the anus or urethra. Some studies have suggested that pharyngeal gonorrhea spreads to the anus and urethra, according to the researchers.

The study was also limited to men; it has yet to be determined whether this Listerine would have the same affect for gonorrhea positive women.

It's important to note Listerine did not fund the study.

Mouthwash has been shown to provide additional benefits to oral health. A 2005 study found it can treat and prevent both gingivitis and periodontitis. Mouth rinses can reach about 100 percent of the mouth’s surfaces, and could be a supplementation to brushing, which mainly reaches the teeth. A germ-fighting mouthwash combined with a regular brushing and flossing routine can greatly improve the likelihood of eliminating the germs that cause oral health problems.

Chow and his team are currently running an even larger trial on 500 men to see if Listerine is effective against gonorrhea bacteria over a longer follow-up period. They’re also going to test a variety of different Listerine products and other mouthwash brands to see which formulas are most effective against gonorrhea in petri dishes.

Listerine could potentially decrease the rate of gonorrhea if proven to be 100 percent effective.

Source: Chow EPF, Howden BP, Walker S et al. Antiseptic mouthwash against pharyngeal Neisseria gonorrhoeae: a randomised controlled trial and an in vitro study. Sex Transm Infect. 2016.

See Also:

Gonorrhea Symptoms In Men

Gonorrhea Symptoms In Women