Mass tort litigation to watch in 2026

By Diana Novak Jones

Jan 5 (Reuters) - The year ahead promises major developments in some of the most closely watched mass tort cases. Courts are likely to issue key rulings in long-running fights over products like Johnson & Johnson's talc-based products and Bayer's Roundup weedkiller, while a high-profile appeal could revive hundreds of lawsuits alleging Kenvue's Tylenol is linked to autism. Meanwhile, the litigation over blockbuster weight loss drugs is heating up – and the viability of lawsuits against makers of so-called "ultra-processed foods" will be tested. Here are some of the top product liability cases to watch in 2026.

TYLENOL

A U.S. appeals court in New York is weighing whether to revive hundreds of lawsuits brought against Kenvue and other companies over claims that the popular painkiller Tylenol or generic versions of it are to blame for their children’s autism or attention deficit hyperactivity disorder diagnoses. Kenvue has long maintained that Tylenol is safe and does not cause autism.

U.S. District Judge Denise Cote dismissed the lawsuits in 2024, after criticizing the methodology that was used by the expert witnesses the plaintiffs relied on to make their claims. But in November, the 2nd U.S. Circuit Court of Appeals questioned whether Cote had improperly excluded evidence in making her decision.

President Donald Trump's warnings about Tylenol and Kenvue’s planned $40 billion merger with Kimberly-Clark have put the litigation under intense scrutiny, raising questions about whether the lawsuits could complicate the deal. In September, Trump and Health Secretary Robert F. Kennedy Jr claimed the painkiller might be linked to autism, and Trump urged pregnant women not to take it, injecting political controversy into the legal battle.

There is no firm evidence of a link between Tylenol or its active ingredient acetaminophen and autism. Medical groups, including the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists, have said acetaminophen is the recommended first-line medication for pain and fever during pregnancy, but should be taken at the lowest possible dose.

ROUNDUP

This year could be pivotal in the long-running litigation over claims that Bayer's Roundup causes cancer. The U.S. Supreme Court may decide whether to weigh in on an issue that could prevent thousands of lawsuits from moving forward.

The company is facing claims from approximately 65,000 plaintiffs and potentially billions of dollars in damages over the widely-used weedkiller in both federal and state courts. It has asked the high court to rule that the federal law governing pesticides preempts state law claims over the product, a decision that could dramatically reduce the number of cases pending.

The chance of the court taking up the issue jumped in December when the Trump administration urged the Supreme Court to take up Bayer’s appeal, saying the company’s reading of the law was correct.

The German pharmaceutical and biotechnology company, which acquired Roundup as part of its $63 billion purchase of Monsanto in 2018, has said that decades of studies have shown Roundup and its active ingredient, glyphosate, are safe for human use.

TALC

Lawsuits alleging Johnson & Johnson’s baby powder caused ovarian cancer are expected to ramp back up in the new year, after a lengthy hiatus prompted by the company’s three unsuccessful attempts to resolve the litigation through bankruptcy.

The ovarian cancer cases make up the bulk of the remaining claims from more than 67,000 plaintiffs who say they developed cancer after using its baby powder and other talc products, according to court filings.

More of these trials are expected to kick off in state court this year. Trials have not yet begun in the federal cases, which have been centralized in New Jersey. A special master is expected to issue a ruling in the coming weeks re-evaluating the experts and scientific evidence behind the plaintiffs’ claims.

The company has said its products are safe, do not contain asbestos and do not cause cancer. J&J stopped selling talc-based baby powder in the U.S. in 2020, switching to a cornstarch product.

WEIGHT LOSS DRUGS

Novo Nordisk and Eli Lilly, makers of blockbuster weight loss drugs, are facing two separate waves of lawsuits over the alleged side effects of the wildly popular products. So far there are about 3,000 lawsuits, but that number is likely to grow, as a KFF poll from November found that about one in five adults has taken one of the drugs, known as GLP-1s.

One group of lawsuits alleges the drugs, including Novo Nordisk's Ozempic, Wegovy and Saxenda and Eli Lilly's Trulicity, can trigger a condition that can lead to blindness. A larger group of lawsuits claims the drugs cause paralysis of the gastrointestinal tract, a condition known as gastroparesis.

The companies have refuted the claims, arguing in court filings that the risk of gastroparesis is well-publicized and that the companies are unable to change the drugs' design without the approval of the U.S. Food and Drug Administration.

ULTRA-PROCESSED FOODS

Lawsuits against major food and beverage companies over so-called “ultra-processed foods” are currently just pending in two courts, but plaintiffs' attorneys say the cases could lead to a sweeping legal battle reminiscent of the litigation over opioids or tobacco.

The claims, which accuse companies of knowingly manufacturing addictive and harmful products and then marketing them to children, were first brought by a Philadelphia man in a 2024 lawsuit alleging that ultra-processed foods were to blame for his type 2 diabetes and non-alcoholic fatty liver disease diagnoses when he was a child. Although a judge dismissed his case in August, he has asked to file a new complaint.

A lawsuit filed by the city of San Francisco in December will test whether these claims have a better chance of succeeding when brought on behalf of government entities because their cases can make claims about population-wide effects.

The companies have pushed back against the allegations, with one industry group arguing that demonizing processed foods misleads consumers and exacerbates health disparities.