Daily rinsing and gargling with Listerine mouthwash could help control the spread of gonorrhoea, a study in Australia has found. Gonorrhoea is a mild, sometimes asymptomatic bacterial infection that can cause infertility, sterility and even death in rare cases. The bacterial infection also increases the risk of contracting HIV. Gonorrhoea can easily be passed between people through unprotected vaginal, oral or anal sex, as well as sharing vibrators or other sex toys that have not been washed or covered with a new condom each time they are used.
Listerine was first invented in the late 19th century, and as early as 1879, manufacturers claimed the disinfectant was effective at both cleaning floors and curing gonorrhoea. But it is only over 100 years later that scientists are testing this hypothesis.
For the study, the researchers conducted a lab experiment and then a clinical trial with gay and bisexual men to see if Listerine could treat gonorrhoea.
For the lab experiment, they exposed the bacteria for one minute to the brand’s Cool Mint and Total Care products, which contain about 22 percent alcohol. They also exposed the bacteria to saline (salt water) for comparison. The two Listerine products inhibited the growth of the bacteria over two days in the lab, compared to saline.
For the trial, 58 men with gonorrhoea throat infections were asked to gargle with Listerine’s Cool Mint mouthwash or saline for one minute. After five minutes, the researchers swabbed the participants’ mouths in two spots.
Overall, the researchers found that 52 percent of men who gargled with the mouthwash tested positive for gonorrhoea, compared to 84 percent of those who gargled with saline.
To be clear, the study did not find evidence that Listerine actually cures gonorrhoea, but it did find that the over-the-counter mouthwash kills enough of the bacteria to render the disease absent from the mouths of about half of those infected.
The researchers are conducting a larger trial to confirm the results and see whether the use of mouthwash could curb the spread of gonorrhoea. They must also establish how long the apparent effects of using the mouthwash lasted.
The researchers do not know if it’s the alcohol content or another ingredient or combination of ingredients in Listerine that killed the bacteria. Therefore, gargling with, say, a shot of vodka may not necessarily have any protective effect. n