Results of a study published in Virus Research found that gargling with a single-agent antiseptic mouth rinse may be associated with a mild decrease in the rate of COVID-19 transmission.

Several antiseptic mouth rinses have shown potential antiviral activity against SARS-CoV-2 infectivity in vitro, however, the antiseptic agent responsible for this effect was not clear. To address this knowledge gap, researchers evaluated the antiviral activity of 10 antiseptic agents against SARS-CoV-2. Of these agents, benzalkoniumchloride (BAC) was most effective in vitro and subsequently selected for further analysis in vivo.

On the basis of these findings, researchers conducted a randomized, placebo-controlled clinical trial that assessed the antiviral activity of mouth rinses containing BAC against SARS-CoV-2 among 24 infected patients. Patients were randomly assigned to either the BAC group (n=18) or the placebo group (n=6). All patients provided oropharyngeal specimens for viral load testing via reverse transcription quantitative-polymerase chain reaction. Samples were provided at baseline, as well as at 15 and 30 minutes after patients gargled with mouth rinses containing either BAC or placebo.

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Among patients in the BAC and placebo groups, the median age was 28.5 (range, 20-62) and 31 (range, 22-73) years, respectively. Most patients (n=22) had mild COVID-19-related symptoms and had been receiving care in an outpatient setting.

Among patients in the BAC group, viral antigen concentrations decreased in 3 patients after gargling with mouth rinses containing BAC. However, gargling with BAC had no effect on patients’ SARS-CoV-2 viral load count. For 1 patient in the placebo group with a detectable viral load, analysis of oropharyngeal samples showed no decrease in viral activity.

This study was limited by its small sample size and the inclusion of only patients with significantly increased SARS-CoV-2 viral loads.

According to the researchers, these “results indicate that the oral application of BAC as [an] antiseptic mouth rinse only mildly reduces viral infectivity in vivo, despite its high efficacy in vitro.” They concluded that “further studies are required to study the clinical effects of antiseptics” with 2 or more agents.


Meister TL, Gottsauner J-M, Schmidt B, et al. Mouth rinses against SARS-CoV-2 – high antiviral effectivity by membrane disruption in vitro translates to mild effects in a randomized placebo-controlled clinical trial Virus Res. 2022;316:198791. doi:10.1016/j.virusres.2022.198791