Johnson & Johnson has long marketed Listerine Cool Mint as a must-have for oral hygiene, a product that “kills 99% of germs.” But for millions of consumers, this daily habit may carry hidden dangers. In a new lawsuit, plaintiffs claim that rather than eliminating harmful bacteria, Listerine could foster cancer-linked microbes. This lawsuit challenges consumers’ fundamental trust in the products they use every day, asking whether they’ve been sold a false promise cloaked in a bottle of minty green.

A Mouthwash That Could Be Spreading Disease

Listerine Cool Mint, marketed to “kill 99% of germs that cause bad breath, plaque & gingivitis,” has become a staple in households worldwide. But contrary to this carefully cultivated image, scientific studies have recently suggested that regular use of Listerine might, in fact, encourage the proliferation of specific bacteria—Fusobacterium nucleatum and Streptococcus anginosus. These bacteria have been linked to an array of severe diseases, including colorectal, oral, pancreatic, and other gastrointestinal cancers.

According to the legal documents, J&J and Kenvue not only failed to disclose these risks but actively promoted the mouthwash as safe and beneficial for daily use, inviting consumers to use it twice daily for optimal results.

The lawsuit alleges that the company misrepresented the product’s safety, downplaying the adverse effects on the microbiome—effects that could ultimately result in significant health consequences. Fusobacterium nucleatum, for instance, is noted for its resilience in acidic environments, which allows it to travel from the mouth to the gut, potentially fostering tumor growth in the colon. The legal complaint highlights this as a direct contradiction to the marketing language that promotes Listerine as a tool for a “fresher and cleaner” mouth.

Johnson & Johnson’s Silence

Despite these revelations, J&J and Kenvue have not updated their product warnings, packaging, or marketing materials to reflect any of these newly uncovered risks. The lawsuit argues that consumers—having relied on the brand’s reputation for safety—have been left in the dark about the potential dangers lurking in their daily hygiene routine. By failing to disclose that Listerine use could increase cancer risks, the complaint asserts, J&J has committed not only a breach of trust but a fundamental violation of consumer rights under California’s consumer protection laws.

For years, J&J has marketed its mouthwash products as rigorously tested and safe, touting over 50 clinical trials as evidence of Listerine’s efficacy and tolerability. However, as the lawsuit points out, these studies did not publicly reveal the possibility of adverse effects related to microbial imbalance. In fact, J&J’s claims that the product “kills 99%” of germs appear to mislead consumers into thinking they are eliminating harmful bacteria, when they might be setting the stage for even more dangerous bacterial growth.

Trust, Safety, and Corporate Accountability

This case is emblematic of a broader issue that pervades the pharmaceutical and consumer goods industries: the prioritization of profit over transparency and consumer welfare. If J&J, with its long-standing reputation as a “family-friendly” brand, can allegedly overlook such a grave health risk, what does this mean for other products and brands that consumers trust daily? The lawsuit suggests that rather than issuing a voluntary recall or revising their warnings, J&J and Kenvue have chosen to press forward, potentially exposing millions to unnecessary risk—all while benefiting from consumer ignorance.

The harm isn’t merely theoretical. By fostering conditions in which harmful bacteria thrive, Listerine could contribute to chronic and deadly health problems that burden individuals, families, and healthcare systems alike. If these allegations are substantiated, they would imply that countless consumers have unknowingly increased their cancer risks simply by following the recommended usage guidelines on the bottle.

A Systemic Failing and the Need for Regulatory Oversight

Ultimately, this case highlights a critical gap in the current regulatory framework, which relies heavily on manufacturers to self-report potential health hazards.

It brings to the fore the question of whether self-regulation is feasible in an industry where the incentive to downplay risks in the pursuit of profit is so strong. Federal law does require companies to update their labeling when new risks become known, yet the this lawsuit argues that J&J has ignored these mandates, thereby demonstrating a disregard for both the law and consumer safety.

But we’re not surprised by this, are we?