Bayer wins key U.S. Roundup cancer trial

On October 29, 2026, a jury in St. Louis unanimously ruled in favor of Bayer and its Monsanto unit, dismissing claims by three women that the Roundup weedkiller caused their cancer. The verdict, which rejected the plaintiffs’ allegations of design defects and negligence, is the first Roundup trial outcome to be reached in the United States following a June U.S. Supreme Court ruling that curtailed certain legal theories against the company.

The three plaintiffs, Theresa Aretino, Cynthia Fernandez and Betty Larkin, alleged they had regularly used Roundup and later developed non-Hodgkin lymphoma. They sued Monsanto in 2020, arguing that the herbicide was defectively designed, unreasonably dangerous and that Bayer was negligent in selling it. The jury unanimously rejected these claims, siding fully with Bayer.

Fernandez died before the trial began, but her claims were included in the case. The three women are not participating in Bayer’s proposed settlement of other Roundup lawsuits, so their case proceeded to this test trial. The verdict strengthens Bayer’s litigation position as it confronts large-scale exposure from remaining claims.

Before the Supreme Court decision earlier in 2026, most Roundup lawsuits focused on allegations that Bayer failed to warn consumers on product labels about cancer risks. The Supreme Court ruled that federal law requires herbicide makers to use the exact label approved by the U.S. Environmental Protection Agency, effectively blocking failure-to-warn claims based on the absence of a cancer warning.

In response, lawyers in the St. Louis case pursued alternative legal theories, claiming Roundup was defectively designed and should not have been sold. Bayer has argued that these design-defect and negligence claims are also foreclosed by the Supreme Court ruling, while plaintiffs’ attorneys have maintained they remain viable. The St. Louis verdict represents an early test of these strategies in the post-ruling environment.

Bayer’s U.S. general counsel and global head of litigation, Bill Dodero, said the verdict shows that plaintiffs who pursue claims after the Supreme Court’s Durnell ruling will face significant challenges in establishing viable claims and proving them in court. The company continues to deny that Roundup causes cancer and cites decades of studies in support of glyphosate’s safety.

While litigating individual cases, Bayer is also seeking to resolve a large portion of its Roundup exposure through a proposed $7.25 billion settlement. That agreement aims to settle tens of thousands of lawsuits and is currently under review by a Missouri state court judge in St. Louis. The St. Louis verdict may influence perceptions of the strength of remaining claims as that review proceeds.

Bayer faces around 65,000 claims in U.S. state and federal courts from individuals who say they developed cancer after using Roundup at home or at work. The Roundup litigation has weighed on the company since its 2018 acquisition of Monsanto, costing it billions of dollars and contributing to pressure on its share price.

Regulatory and scientific assessments of glyphosate, Roundup’s active ingredient, remain divided. The International Agency for Research on Cancer concluded in 2015 that glyphosate was “probably carcinogenic” to humans, while Bayer disputes that conclusion as an outlier based on flawed methodology. The Environmental Protection Agency has previously found that glyphosate is probably not carcinogenic and is in the middle of a new review of its safety.