Risk assessment and pharmacokinetic modeling of incidental ingestion of ethanol from mouthwash

Mouthwashes containing ethanol for antiseptic properties have a long history of use and well-established oral hygiene benefits by significantly enhancing the control of dental biofilm and reducing gingival inflammation. Despite the substantial health benefits from ethanol-containing mouthwashes, there has been ongoing scrutiny by regulatory and health authorities of products containing ethanol resulting from the classification of consumption of alcohol-containing beverages as a potential carcinogen. Unlike alcohol-containing beverages, mouthwash products are not intended to be ingested, and the potential ethanol exposure is substantially lower for mouthwash products. Therefore, we conducted a risk assessment that benchmarked estimated and modeled incidental exposure to ethanol in mouthwash products against endogenous blood levels, dietary exposure, and health-based guidance values for ethanol. All mouthwash-use scenarios, including average, 90th-percentile, and maximum-label use, resulted in relatively low estimated ethanol exposures that were below various reference and health-based guidance values (HBGVs), including the HBGV of 1 g/day for ethanol (16.7 mg/kg/day in a 60-kg human), a conservative value that is considered to be protective against all chronic health endpoints, including cancer. The findings suggest that ethanol from mouthwash does not significantly contribute to systemic levels of ethanol, falls within dietary intake levels, and remains below HBGVs. Taken together, this assessment concludes that incidental oral exposure of ethanol-containing mouthwashes represents a de minimis health risk.