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Effect of Antiseptic Mouthwash/Gargling Solutions on SARS-CoV-2 Viral Load: A Randomized Clinical Trial
Sepideh Banava1,2,3, Allan Radaic4, Kamarajan Pachiyappan4
1Division of Oral Epidemiology & Dental Public Health, Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, California, USA.
Background:
The COVID-19 pandemic has caused significant global mortality. Despite declining infection rates, new variants of SARS-CoV-2 continue to emerge, necessitating new prevention strategies.
Objective:
This study aimed to evaluate the effect of four over-the-counter (OTC) antiseptic mouthwash/gargling solutions in the U.S., compared with a distilled water control, on SARS-CoV-2 viral load across multiple oral and oropharyngeal sample types.
Methods:
This pilot single-center randomized controlled clinical trial enrolled adults in the San Francisco Bay Area, California, who tested positive for COVID-19. Participants were randomized to distilled water, chlorine dioxide, hydrogen peroxide, cetylpyridinium chloride, and essential oils. Participants were instructed to rinse and gargle four times daily for four weeks using standardized instructions to ensure protocol adherence. Samples were collected on Days 1, 7, and 28 and analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The primary outcome was the change in SARS-CoV-2 viral load from baseline to Day 28, assessed using cycle threshold (Ct) values. Secondary outcomes included self-reported clinical symptoms and hospitalization.
Results:
Forty-nine participants completed the study. No mouthwash demonstrated a statistically significant reduction in SARS-CoV-2 viral load over time. Cetylpyridinium chloride showed a transient increase in Ct values on Day 7 that was not sustained on Day 28. At baseline, throat swab samples had the lowest Ct values across all sample types. Due to limited subgroup sample sizes for secondary outcome measures, no statistical or moderator analyses were conducted.
Conclusion:
Further large-scale randomized trials are needed before recommending antiseptic mouthwashes for SARS-CoV-2 prevention or management.
Trial Registration:
ClinicalTrials.gov NCT04409873.
Insights
This study found no significant reduction in SARS-CoV-2 viral load using over-the-counter antiseptic mouthwashes. Further large-scale trials are necessary to determine the efficacy of these mouthwashes for COVID-19 prevention or management.
Area of Science:
- Virology
- Public Health
- Clinical Trials
Background:
- The COVID-19 pandemic caused significant global mortality, with emerging SARS-CoV-2 variants necessitating novel prevention strategies.
- Over-the-counter (OTC) antiseptic mouthwashes are widely available and used for oral hygiene.
Purpose of the Study:
- To evaluate the efficacy of four OTC antiseptic mouthwash solutions in reducing SARS-CoV-2 viral load.
- To compare the effects of different mouthwash ingredients against a distilled water control.
Main Methods:
- A pilot randomized controlled trial involving adults with COVID-19 in the San Francisco Bay Area.
- Participants used distilled water, chlorine dioxide, hydrogen peroxide, cetylpyridinium chloride, or essential oils mouthwash four times daily for four weeks.
- SARS-CoV-2 viral load was measured using RT-qPCR on oral and oropharyngeal samples collected at baseline, Day 7, and Day 28.
Main Results:
- No statistically significant reduction in SARS-CoV-2 viral load was observed with any mouthwash over the 28-day study period.
- Cetylpyridinium chloride showed a temporary increase in viral load (lower Ct values) at Day 7, which was not sustained.
- Throat swab samples exhibited the lowest viral load (highest Ct values) at baseline across all sample types.
Conclusions:
- Antiseptic mouthwashes did not demonstrate a statistically significant effect on SARS-CoV-2 viral load in this pilot study.
- Larger-scale randomized trials are required to definitively assess the role of antiseptic mouthwashes in SARS-CoV-2 prevention or management.
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