Dental researchers in Australia, M.J. McCullough and C.S. Farah, recently published a review of the data on mouthwash use and the risk of oral cancer.  The researchers reviewed the epidemiological evidence and the proposed mechanism of carcinogenicity of mouthwash and concluded that there is now sufficient evidence that regular use of alcohol containing mouthwashes contributes to the risk of oral cancer.  The research suggests that the risk is the result of the metabolic conversion of ethanol to acetaldehyde, a mutagenic and carcinogenic compound.  Several Listerine branded mouthwashes topped the researcher’s list due to the high level of alcohol (ethanol) contained in these products, as high as 26 percent.  The newly established connection between oral cancer and regular mouthwash use raises the potential for legal claims against mouthwash manufacturers for personal injuries and deceptive or fraudulent marketing.  The abstract is included below.  

The role of alcohol in oral carcinogenesis with particular reference to alcohol-containing mouthwashes 

MJ McCullough,* CS Farah  

Worldwide, oral cancer represents approximately 5 per cent of all malignant lesions, with over 800 new intra-oral squamous cell carcinomas registered in Australia each year. Despite recent advances in therapy, the five-year survival rate remains around 50 per cent and the sequelae of treatment can be seriously debilitating. It has been long established that smoking and alcohol consumption are risk factors linked to the development of oral cancer. This review assesses the epidemiological evidence, supportive in vitro studies and mechanism by which alcohol is involved in the development of oral cancer. Further, we review the literature that associates alcohol-containing mouthwashes and oral cancer. On the basis of this review, we believe that there is now sufficient evidence to accept the proposition that alcohol-containing mouthwashes contribute to the increased risk of development of oral cancer and further feel that it is inadvisable for oral healthcare professionals to recommend the long-term use of alcohol-containing mouthwashes.