A pending class action accuses Listerine Cool Mint Antiseptic of promoting bacteria that have been linked to several cancers, and of hiding that risk from consumers. The Listerine cancer lawsuit, Vasseur v. Johnson & Johnson Consumer, Inc. et al., was filed in September 2024 in federal court in California and names both Johnson & Johnson and Kenvue Inc., the company that took over J&J’s consumer health brands in 2023. As of mid-2026 the case is still in its earliest stages, with no rulings, no motions to dismiss on the docket, and no settlement. Consumers do not need to do anything right now.1Top Class Actions. Regular Listerine Use Associated With Bacteria Cancer Class Action Claims
What the Lawsuit Claims
Plaintiff Paige Vasseur filed the complaint on September 3, 2024, in the U.S. District Court for the Central District of California, Case No. 2:24-cv-07487.1Top Class Actions. Regular Listerine Use Associated With Bacteria Cancer Class Action Claims It targets one product: Listerine Cool Mint Antiseptic. The suit alleges that daily use increases two bacteria in the mouth, Fusobacterium nucleatum and Streptococcus anginosus, both of which have been associated in prior research with colorectal, esophageal, oral, pancreatic, and breast cancers.2ClassAction.org. Listerine Class Action Lawsuit Says Regular Use Can Increase Cancer Causing Bacteria
The false-advertising theory turns on a mismatch between the label and the alleged effect. Listerine Cool Mint packaging says the product kills “99% of germs,” which the complaint argues leads reasonable buyers to believe it eliminates harmful bacteria. The suit says the mouthwash does the opposite for certain organisms, feeding growth of cancer-linked bacteria while the label stays silent on that risk.2ClassAction.org. Listerine Class Action Lawsuit Says Regular Use Can Increase Cancer Causing Bacteria
The complaint invokes California’s Unfair Competition Law, False Advertising Law, and Consumer Legal Remedies Act, and argues the product is “misbranded and/or adulterated” under the federal Food, Drug, and Cosmetics Act.1Top Class Actions. Regular Listerine Use Associated With Bacteria Cancer Class Action Claims2ClassAction.org. Listerine Class Action Lawsuit Says Regular Use Can Increase Cancer Causing Bacteria
The Study the Case Rests On
The scientific spine of the complaint is a 2024 paper in the Journal of Medical Microbiology, “The effect of daily usage of Listerine Cool Mint mouthwash on the oropharyngeal microbiome: a substudy of the PReGo trial,” by a team at the Institute of Tropical Medicine in Antwerp, Belgium, led by Jolein Laumen and Chris Kenyon.3PubMed. The Effect of Daily Usage of Listerine Cool Mint Mouthwash on the Oropharyngeal Microbiome
Fifty-nine men used Listerine Cool Mint daily for three months and a placebo mouthwash for another three, in either order. After the Listerine phase, participants had significantly higher levels of Fusobacterium nucleatum and Streptococcus anginosus than at baseline. Levels of Actinobacteria, which play a role in regulating blood pressure, dropped.4Dental Tribune. Listerine Mouthwash Shown to Disrupt Oral Microbiome in Men
The researchers were cautious about how far the findings should be pushed. Dr. Laumen said consumers “should be aware of the potential implications” of daily mouthwash use and that “long-term usage should be guided by healthcare professionals.” The team also flagged the small sample and the absence of data on smoking and diet, said they were “reluctant to draw substantial conclusions,” and called for larger studies.5Microbiology Society. Commonly Used Alcohol Based Mouthwash Brand Disrupts the Balance of Your Oral Microbiome
What the Label Actually Says
Listerine Cool Mint Antiseptic is sold as an over-the-counter drug under FDA Monograph M022 for oral healthcare products.6DailyMed. Listerine Clinical Solutions Gum Health Drug Facts Its active ingredients are eucalyptol, menthol, methyl salicylate, and thymol, and it contains 21.6% alcohol. The label warns against use in children under 12, tells users not to swallow, refers accidental ingestion above a rinse amount to Poison Control, and advises consulting a dentist if symptoms persist.7DailyMed. Listerine Cool Mint Antiseptic Drug Facts Label
Nothing on the label mentions effects on the oral microbiome or any association with cancer-linked bacteria. That omission is the core of the complaint. Listerine Antiseptic also holds the American Dental Association’s Seal of Acceptance, which describes the product as “safe” and effective in helping “prevent and reduce gingivitis (and plaque above the gumline), when used as directed.”8American Dental Association. Listerine Antiseptic ADA Seal of Acceptance
Who Is Being Sued
Both Johnson & Johnson and Kenvue Inc. are named as defendants. Kenvue became a fully independent company on August 23, 2023, after separating from J&J through an IPO and spinoff, and Listerine is now one of its flagship brands alongside Tylenol, Band-Aid, and Neutrogena.9Kenvue Inc. Kenvue Becomes a Fully Independent Company J&J remains in the case presumably because some of the conduct at issue predates the split. Public filings do not spell out how litigation liability was allocated between the two companies.
Who Is Covered and What to Do
The complaint seeks to represent two groups: all U.S. consumers who bought Listerine Cool Mint Antiseptic for personal or household use within the applicable limitations period, and a California-specific subclass.2ClassAction.org. Listerine Class Action Lawsuit Says Regular Use Can Increase Cancer Causing Bacteria Vasseur is represented by Trenton R. Kashima of Milberg Coleman Bryson Phillips Grossman PLLC and Jonathan Shub of Shub & Johns LLC.1Top Class Actions. Regular Listerine Use Associated With Bacteria Cancer Class Action Claims
There is no claims process. If the case is later certified as a class action and reaches a settlement, affected purchasers would typically receive notice with instructions for filing a claim at that point.2ClassAction.org. Listerine Class Action Lawsuit Says Regular Use Can Increase Cancer Causing Bacteria The suit targets only Listerine Cool Mint Antiseptic; other Listerine products are not part of it.
What the Wider Research Shows
The idea that oral bacteria feed cancer is a real area of science, but far from settled. Fusobacterium nucleatum is a normal resident of the human mouth. A 2024 Nature study found that a subtype called Fna C2 was consistently enriched inside colorectal tumor tissue compared to surrounding healthy tissue, and that people with colorectal cancer were roughly five times more likely to have Fna C2 in their stool than people without the disease.10National Cancer Institute. Colorectal Cancer Fna C2 Bacteria Current thinking is that the bacterium promotes tumor progression rather than initiating cancer.11PMC. Fusobacterium Nucleatum in Colorectal Cancer The National Cancer Institute has said “the jury’s still out” on whether it plays any role in initiation.
Research directly on mouthwash and cancer is mixed. A 2016 INHANCE Consortium pooled analysis of more than 19,000 people found no meaningful overall increase in head and neck cancer risk among mouthwash users, but flagged a subgroup: those who used mouthwash more than once a day for over 35 years had roughly 75% higher odds of head and neck cancer than non-users. No increased risk appeared among people who had never smoked or drunk alcohol.12PMC. Mouthwash and Head and Neck Cancer INHANCE Consortium Pooled Analysis A 2025 systematic review in Cureus covering 15 case-control studies with more than 23,000 participants likewise found no significant link between general mouthwash use and oral cancer, but higher rates among people using it three or more times a day, and among 40-plus-year users.13Cureus. Does Mouthwash Use Affect Oral Cancer Risk A 2020 review in Medicina Oral concluded it “cannot be guaranteed that the use of mouthwash represents an independent risk factor” for head and neck cancer.14PMC. Alcohol Based Mouthwash as a Risk Factor of Oral Cancer
A 2023 review in the International Dental Journal raised a related concern: antimicrobial mouthwashes kill bacteria indiscriminately and can throw off the balance between beneficial and harmful organisms. The authors recommended that use “be limited to specific indications and periods of use that are supported by appropriate lines of evidence.”15PMC. Mouthwash Effects on the Oral Microbiome: Are They Good, Bad, or Balanced The ADA, for its part, has said a recent systematic review and meta-analysis “failed to find an association between mouthrinse use and oral cancer, use of alcohol-containing mouthrinse and oral cancer, or mouthrinse dose response and oral cancer.”16American Dental Association. Mouthrinse (Mouthwash)
A Prior Listerine Case That Could Matter
In 2014, a class action called Bowling et al. v. Johnson & Johnson (Case No. 1:14-cv-03727) was filed in the Southern District of New York, arguing that Listerine Total Care mouthwash falsely claimed to “restore enamel.” A federal judge dismissed the case that November, ruling that the plaintiffs’ state-law claims were preempted by federal law because the FDA sets labeling requirements for such products. The plaintiffs appealed, then withdrew the appeal in June 2015 without disclosing why.17Truth in Advertising. Listerine Total Care Mouthwash18Top Class Actions. Listerine Total Care Class Action Lawsuit Dismissed
The Bowling ruling could shape the current case. Vasseur’s complaint argues that Listerine Cool Mint’s labeling violates both California consumer statutes and the federal Food, Drug, and Cosmetics Act. If the defendants argue that the FDA, through its OTC monograph system, dictates what the label must say and that state law cannot pile on additional requirements, Bowling gives them a favorable precedent.
Where the Case Stands
As of June 2026, Vasseur v. Johnson & Johnson Consumer, Inc. et al. is still pending in the Central District of California with no public record of motions to dismiss, class certification proceedings, or settlement talks.1Top Class Actions. Regular Listerine Use Associated With Bacteria Cancer Class Action Claims The case has obstacles ahead: the underlying microbiome science is preliminary, the ADA still endorses the product, and prior Listerine suits have run into federal preemption. Purchasers do not need to file anything now; if the case is later certified and settled, notice would follow at that stage.