Roundup Cancer Lawsuits Against Monsanto Explained

A plain-language legal guide to the glyphosate litigation: what Roundup is, why tens of thousands of people have sued, what the science and regulators actually say, where the cases stand in 2026, and how mass tort claims work.

Last reviewed: June 2026. This article is general legal information, not legal advice. Reading it does not create an attorney-client relationship.

Key Takeaways Roundup is a widely used weed killer whose active ingredient, glyphosate, sits at the center of one of the largest mass tort litigations in U.S. history. More than 100,000 claims have been filed alleging that Roundup exposure contributed to non-Hodgkin lymphoma; Bayer (which bought Monsanto in 2018) has resolved the large majority but tens of thousands remain pending. U.S. and international regulators are split from the World Health Organization’s cancer research arm on whether glyphosate is carcinogenic — a scientific dispute that drives the litigation. These are individual injury lawsuits, not a single class action. A pending U.S. Supreme Court case and a proposed $7.25 billion settlement could reshape the landscape in 2026. Eligibility, value, and deadlines turn entirely on individual facts. Nothing here guarantees any outcome.

Introduction

Few consumer products have generated as much litigation as Roundup, the glyphosate-based weed killer found on farms, golf courses, roadsides, and garage shelves for decades. What began as a handful of lawsuits grew into one of the largest mass torts in American legal history — well over 100,000 claims brought by people who say long-term exposure to Roundup contributed to their cancer, most often non-Hodgkin lymphoma.

The story sits at the intersection of science, regulation, and law. Government regulators in the United States and much of the world have concluded that glyphosate is unlikely to cause cancer when used as directed. The World Health Organization’s cancer research arm reached a different conclusion in 2015. Juries have heard both sides and, in several high-profile trials, sided with plaintiffs and awarded large verdicts. Appeals, settlements, and now a U.S. Supreme Court case have followed.

This guide explains the litigation in plain language: what Roundup and glyphosate are, why the lawsuits were filed, what cancers are alleged, how the science and the regulators diverge, the major verdicts and settlement developments, who is generally involved, what evidence tends to matter, and how mass tort litigation differs from a class action. It closes with a detailed FAQ and an educational checklist. The aim is to inform — not to promise outcomes or substitute for advice from a qualified attorney about a specific situation.

A note on this litigation: the allegations described below are claims made by plaintiffs in court. Monsanto and its parent company, Bayer, deny that Roundup causes cancer and point to regulatory findings supporting the product’s safety. Courts and juries have reached differing results, and key questions remain unresolved.

What Is Roundup?

Roundup is a brand of broad-spectrum herbicide — a weed killer designed to kill a wide range of plants rather than target a specific species. It was first brought to market by Monsanto in the 1970s and became one of the best-selling herbicides in the world, especially after the introduction of genetically modified “Roundup Ready” crops engineered to survive being sprayed.

The product’s active ingredient is glyphosate. Over the decades, Roundup has been used across several settings:

• Agricultural use — sprayed on row crops such as corn, soybeans, cotton, and sugar beets, where glyphosate remains the most common herbicide in U.S. farming.
• Residential and lawn-and-garden use — long sold to homeowners for driveways, gardens, and yards. Bayer transitioned U.S. residential formulations away from glyphosate beginning in 2023 to reduce future litigation, a step the company said it took to manage legal risk rather than because of safety concerns.
• Landscaping and groundskeeping — used by professional landscapers, golf course crews, parks departments, and maintenance workers.
• Commercial and industrial applications — applied along rights-of-way, in nurseries, and in other commercial vegetation management.

Key entities to understand

Several names recur throughout the litigation, and distinguishing them helps make sense of the coverage:

Entity	Role in the Roundup story
Roundup	The branded glyphosate-based herbicide at the center of the lawsuits.
Monsanto	The company that developed and sold Roundup; named defendant in most suits.
Bayer	German life-sciences company that acquired Monsanto in 2018 and assumed its liabilities.
Glyphosate	The active chemical ingredient in Roundup and the focus of the scientific dispute.
EPA	U.S. Environmental Protection Agency — the federal regulator of pesticides.
IARC	International Agency for Research on Cancer, the WHO body that classified glyphosate in 2015.

Why Were the Lawsuits Filed?

Plaintiffs in the Roundup litigation generally allege that exposure to the herbicide contributed to their cancer and that the manufacturer should have warned them of that risk. It is important to frame these as allegations: they are contested claims, and Monsanto and Bayer deny them. The legal theories typically include the following.

• Failure to warn. The central claim in most cases — that the company did not adequately warn users of an alleged cancer risk associated with the product.
• Product liability / design defect. Allegations that the product as formulated was unreasonably dangerous.
• Negligence. Claims that the company failed to exercise reasonable care in testing, manufacturing, or marketing.
• Failure to test. Assertions that the company did not adequately study the product’s long-term health effects.
• Alleged corporate knowledge. Plaintiffs have pointed to internal documents they argue show the company was aware of, or worked to influence, the science. The company disputes these characterizations.

Underlying all of this is a genuine scientific dispute about whether glyphosate causes cancer in humans — a question on which expert witnesses, regulators, and researchers have disagreed. Because the science is contested, the litigation has turned heavily on competing expert testimony and on legal questions about who gets to decide what a product label must say.

Roundup claims are one example of a broader category of cases known as mass torts, in which many individuals allege harm from the same product or conduct. Readers researching the wider field may also find general background on product liability and toxic tort claims useful for context.

What Types of Cancer Have Been Alleged?

The cancer most frequently alleged in the Roundup litigation is non-Hodgkin lymphoma (NHL), a cancer of the lymphatic system. Within that category, plaintiffs have alleged specific subtypes, including:

• Non-Hodgkin lymphoma (NHL) — the primary cancer alleged across the litigation.
• Diffuse large B-cell lymphoma (DLBCL) — a common and aggressive NHL subtype frequently cited in claims.
• Other lymphomas and related cancers — some claims have referenced additional subtypes such as follicular lymphoma or chronic lymphocytic leukemia, though NHL remains the core allegation.

Linking a specific cancer to a specific exposure is medically and legally complex. Several concepts recur:

Medical causation, exposure, and latency

• Medical causation. Courts distinguish between whether a substance can cause a disease in general (general causation) and whether it did so in a particular person (specific causation). Both are contested in Roundup cases and depend on expert testimony.
• Exposure duration and intensity. Cases often focus on how long and how heavily a person used Roundup — for example, years of regular spraying versus occasional household use.
• Latency. Many cancers develop years after exposure. This lag period, called latency, affects both the medical analysis and legal filing deadlines.

Medical uncertainty Whether glyphosate causes non-Hodgkin lymphoma in any given individual is not medically settled. Epidemiological studies have reported mixed results, and a cancer diagnosis alone does not establish that Roundup was the cause. These questions are evaluated case by case with medical and scientific experts.

What Is Glyphosate?

Glyphosate is a synthetic compound first commercialized as a herbicide by Monsanto in 1974. It works by blocking an enzyme pathway (the shikimate pathway) that plants need to grow — a pathway not found in humans or animals, which is part of why regulators have historically considered it low-risk to people. It is now the most widely used herbicide in the world.

The scientific debate is not really about whether glyphosate kills weeds; it is about whether long-term exposure raises cancer risk in humans. Here the expert bodies diverge sharply, and that divergence is the engine of the litigation.

EPA vs. IARC: why the conclusions differ

Two assessments are cited more than any others, and they reach opposite conclusions:

Body	Conclusion on glyphosate	Basis
U.S. EPA	Not likely to be carcinogenic to humans at label-relevant doses	Reviewed a large dataset including regulatory studies; aligned with many international regulators
IARC (WHO)	Probably carcinogenic to humans (Group 2A)	2015 hazard review; cited limited human evidence on NHL, sufficient animal evidence, and strong evidence of genotoxicity

Several factors explain the gap. The two bodies were answering different questions and using different evidence sets. IARC conducts hazard identification — asking whether a substance is capable of causing cancer under some conditions — and relied substantially on publicly available studies and mechanistic data. The EPA conducts risk assessment — asking whether real-world use as directed poses a meaningful risk — and considered a broader pool of studies, including industry-submitted regulatory data. The two also weighed the evidence on genotoxicity (DNA damage) differently.

Other regulators have largely aligned with the EPA. The European Food Safety Authority, the European Chemicals Agency, and food-safety authorities in several countries have concluded glyphosate is unlikely to pose a carcinogenic risk as used, while IARC has remained an outlier among regulatory-style reviews in its hazard classification.

The U.S. picture is not entirely static, however. In 2022, the U.S. Court of Appeals for the Ninth Circuit ordered the EPA to revisit its conclusion that glyphosate is “not likely” to cause cancer, finding the agency’s reasoning inconsistent, and the EPA subsequently withdrew the human-health portion of its interim registration decision while it reevaluates. The agency has said its underlying scientific view has not changed, but the formal record remains under review — a nuance that figures into the legal arguments described below.

Why this matters legally: a hazard classification (“can it cause cancer in some scenario?”) is not the same as a finding that a product caused a specific person’s cancer. Plaintiffs cite IARC and supporting studies; defendants cite the EPA and the global regulatory consensus. Juries have had to choose between dueling expert narratives.

A Brief Timeline of the Litigation

The litigation has unfolded over roughly a decade. The milestones below capture the major turning points.

Year	Milestone
1974	Glyphosate first commercialized by Monsanto as the herbicide Roundup.
2015	IARC classifies glyphosate as “probably carcinogenic to humans” (Group 2A), helping spur litigation.
2016	Federal Roundup cases consolidated into multidistrict litigation (MDL 2741) in the Northern District of California.
2018	First major trial (Johnson v. Monsanto) ends in a large plaintiff verdict, later reduced on appeal. Bayer acquires Monsanto.
2019	Additional high-profile California verdicts (Hardeman; Pilliod) favor plaintiffs; damages later reduced.
2020	Bayer announces a roughly $10–11 billion program to resolve a large share of existing claims.
2021–22	A proposed fund for future claims is rejected by the MDL judge; the Ninth Circuit orders the EPA to revisit its cancer finding.
2024–25	Federal circuit courts split on whether federal pesticide law preempts failure-to-warn claims, setting up Supreme Court review.
2026	Supreme Court hears Monsanto v. Durnell on preemption; a proposed $7.25 billion class settlement receives preliminary approval and faces objections.

Major Roundup Verdicts and Settlement Developments

The litigation’s early trials produced several large jury verdicts for plaintiffs, which drew national attention even though appellate courts frequently reduced the damage awards. Those early results helped drive both the volume of new filings and the company’s move toward large-scale settlement.

Rather than focus on specific dollar figures that shift on appeal, it is more useful to understand the overall pattern:

• Early plaintiff verdicts. The first bellwether-style trials in California resulted in verdicts for plaintiffs, some initially in the hundreds of millions or more, with punitive damages later trimmed by trial and appellate courts.
• Mixed results since. Across many subsequent trials in state and federal courts, outcomes have been mixed — some substantial plaintiff verdicts, some defense wins. Results have varied by jurisdiction and by the strength of each plaintiff’s exposure and medical evidence.
• Large-scale settlements. Bayer has resolved the large majority of claims through block settlements with high-volume firms and individual resolutions, committing roughly $10–11 billion to that effort over time.
• Appeals and the bigger legal question. Beyond individual damages, the defendant has pursued a broader legal strategy centered on federal preemption — the argument that federal pesticide law bars state-law failure-to-warn claims when the EPA has not required a cancer warning.

Current status (as of mid-2026) As of June 2026, the litigation remains active. Tens of thousands of claims are still pending — several thousand in the federal MDL in California and more in state courts. Bayer has proposed a $7.25 billion class settlement to resolve current and future non-Hodgkin lymphoma claims; that deal received preliminary approval from a Missouri state court but faces objections from some plaintiffs’ lawyers over its structure and value, and a federal judge overseeing the MDL has questioned whether it can bind future claimants. Separately, the U.S. Supreme Court heard argument in Monsanto v. Durnell in April 2026 on the preemption question, with a decision expected by the end of the Court’s term. Because these developments are evolving, anyone affected should confirm the latest status with a qualified attorney rather than relying on any single figure or date.

Who May Be Involved in These Claims?

Whether a particular person has a viable claim depends entirely on individual facts — exposure history, diagnosis, timing, and applicable law — and only a licensed attorney can evaluate a specific situation. As a general educational matter, the litigation has tended to involve people with meaningful, often long-term, Roundup exposure, including:

• Agricultural and farm workers who applied glyphosate products over many seasons.
• Landscapers and lawn-care professionals with routine occupational exposure.
• Groundskeepers and golf course maintenance workers.
• Nursery, parks, and roadside vegetation-management workers.
• Long-term residential users who sprayed Roundup heavily over a period of years.

Exposure alone is not enough. Claims generally also involve a qualifying cancer diagnosis — most commonly non-Hodgkin lymphoma — and must satisfy legal deadlines. No one should assume eligibility or ineligibility based on a general description; these determinations require individualized review.

Important: this section describes general patterns in the litigation. It is not a statement that any reader qualifies, and it makes no promise of compensation. Eligibility is a legal question that depends on the specific facts of each case.

Evidence Often Reviewed in These Cases

Because causation is contested, documentation tends to be central. Attorneys evaluating a potential Roundup claim typically look at categories of evidence such as:

• Medical records and diagnosis. Pathology reports and records confirming the type and timing of the cancer.
• Exposure history. How, where, how often, and for how long the person used or was around Roundup.
• Employment records. For occupational exposure — job duties, dates, and employers that establish a work-related history.
• Purchase records. Receipts, loyalty accounts, or other proof of buying the product, where available.
• Witness testimony. Coworkers, family, or others who can describe the pattern of use.
• Expert opinions. Medical and scientific experts who address general and specific causation.

No single document decides a case; attorneys weigh the full picture against the applicable legal standards.

Mass Tort vs. Class Action: What’s the Difference?

A common misconception is that Roundup cases are a “class action.” They are generally not. The Roundup litigation is a mass tort — a different structure with important consequences for individual plaintiffs.

Feature	Mass Tort	Class Action
Plaintiffs	Many individuals, each with a separate case	One representative group treated as a single class
Damages	Evaluated individually per plaintiff	Typically shared on a common formula
Injuries	Vary person to person	Usually similar across the class
Resolution	Settlements or trials sized to individual facts	One judgment or settlement binds the class

Within a mass tort, related federal cases are often consolidated into a multidistrict litigation (MDL) before a single judge for efficient pretrial handling — here, MDL 2741 in the Northern District of California. Consolidation streamlines discovery and pretrial motions, but each plaintiff’s case remains individual.

Bellwether trials

In large MDLs, the parties select a small number of representative cases, called bellwether trials, to go to trial first. Their outcomes help both sides gauge how juries respond to the evidence and inform broader settlement negotiations — a dynamic that played a significant role in the Roundup settlements.

Readers comparing different ongoing cases may find it helpful to review broader resources on mass tort lawsuits, current active mass torts, and mass tort investigations to understand how Roundup fits among other product and toxic-exposure matters.

Filing Deadlines and the Statute of Limitations

Every state sets a statute of limitations — a legal deadline for filing suit. For injury claims like these, the clock is often measured in years, but the rules vary significantly by state and by the type of claim.

Several wrinkles make deadlines especially important in toxic-exposure cases:

• The discovery rule. In many states, the clock starts when a person knew or reasonably should have known that an injury may be linked to the exposure — not necessarily at first use.
• State-by-state variation. The length of the deadline and how it is calculated differ across jurisdictions.
• Latency. Because cancer can develop years after exposure, the timing of diagnosis often matters a great deal.

Because missing a deadline can permanently bar a claim regardless of its merits, acting promptly and confirming the applicable limitations period with a qualified attorney is critical.

Deadlines are unforgiving. Statutes of limitation can end a claim before it is ever heard. Anyone considering a claim should not wait to learn the specific deadline that applies to their situation.

Frequently Asked Questions

What cancers are linked to Roundup lawsuits?

The lawsuits most commonly allege non-Hodgkin lymphoma (NHL), including subtypes such as diffuse large B-cell lymphoma. Some claims reference related lymphomas. These are alleged links asserted in litigation, not medically established certainties for any individual.

What is glyphosate?

Glyphosate is the active chemical ingredient in Roundup and the most widely used herbicide in the world. It kills plants by blocking an enzyme pathway they need to grow. The dispute in these cases is whether long-term human exposure raises cancer risk.

Is Roundup the same as Monsanto and Bayer?

No. Roundup is the product, Monsanto is the company that made it, and Bayer is the company that bought Monsanto in 2018 and took on its liabilities. Lawsuits typically name Monsanto, now part of Bayer.

Did the EPA say Roundup causes cancer?

The EPA has concluded glyphosate is not likely to be carcinogenic to humans at label-relevant doses, a position shared by many international regulators. A 2022 federal appeals court ordered the EPA to revisit and better explain that finding, and the agency withdrew part of its interim decision while it reevaluates. IARC, the WHO’s cancer research arm, reached a different conclusion in 2015.

Why do regulators and IARC disagree?

They asked different questions with different evidence. IARC performs hazard identification (can it cause cancer under some conditions?) and weighed certain studies and genotoxicity data heavily. The EPA performs risk assessment (does normal use pose a meaningful risk?) using a broader dataset. That difference in method and evidence produced opposite conclusions.

Can homeowners file claims?

Some claims have come from residential users, particularly those with heavy, long-term use. Whether any individual homeowner has a viable claim depends on exposure, diagnosis, timing, and state law, and requires individual legal review. Bayer moved U.S. residential Roundup away from glyphosate starting in 2023.

Is this a class action?

Generally no. The Roundup litigation is a mass tort made up of many individual cases, some consolidated in a federal MDL. A separate proposed class settlement is being litigated in 2026, but the core litigation treats each plaintiff’s claim individually.

What is an MDL?

A multidistrict litigation consolidates related federal cases before one judge for coordinated pretrial proceedings. It improves efficiency, but each case remains separate for purposes of individual facts and damages. The Roundup MDL (2741) sits in the Northern District of California.

How long do these lawsuits take?

There is no fixed timeline. Some cases resolve through settlement; others proceed through discovery, motions, and trial over a period of years. Appeals can extend matters further. Duration depends on the court, the strength of the evidence, and whether the case settles.

Is Roundup banned?

Roundup is not banned in the United States. Bayer reformulated U.S. residential products away from glyphosate beginning in 2023, but glyphosate-based Roundup remains available for agricultural and professional use. Some other countries and localities have imposed restrictions.

How do attorneys evaluate a potential claim?

They typically review the cancer diagnosis and medical records, the nature and duration of Roundup exposure, employment or purchase history, and the applicable statute of limitations, then assess causation with medical and scientific experts. No reputable attorney can promise an outcome.

Can family members bring a wrongful death claim?

In many states, surviving family members or an estate may be able to pursue a claim if a loved one died from an alleged Roundup-related cancer. Eligibility and deadlines vary by state. General background on these claims is available through resources on wrongful death and personal injury law.

What is the $7.25 billion settlement?

It is a proposed class settlement, announced in early 2026, intended to resolve current and future non-Hodgkin lymphoma claims. It received preliminary approval in a Missouri state court but faces objections over its structure and the amount available to claimants, and its ability to bind future plaintiffs has been questioned. It was not final as of mid-2026.

What is the Supreme Court case about?

In Monsanto v. Durnell, argued in April 2026, the Court is considering whether federal pesticide law (FIFRA) preempts state-law failure-to-warn claims when the EPA has not required a cancer warning. The outcome could significantly affect how, and whether, many Roundup claims proceed.

Does it cost money to talk to a lawyer about a claim?

Many attorneys handling these matters offer a free initial consultation and work on a contingency basis, meaning fees come from any recovery rather than upfront. Arrangements vary, so confirm the specific terms with any attorney you consult.

Will I have to go to court?

Not necessarily. Many mass tort claims resolve through settlement without an individual trial. Whether a particular case goes to trial depends on its facts and how the broader litigation develops.

What to Do Next: An Educational Checklist

If you are researching Roundup and a cancer diagnosis — for yourself or a loved one — the following general steps can help you get organized. This is educational information, not legal advice, and not a promise that a claim exists.

1. Prioritize health. Follow your medical team’s guidance first; legal questions come second to treatment and care.
2. Gather medical records. Collect diagnosis and pathology documentation showing the type and date of the cancer.
3. Document the exposure. Write down where, when, how often, and how long Roundup was used, and in what role (work or home).
4. Find supporting records. Locate any employment history, purchase receipts, or witnesses that corroborate the exposure.
5. Note key dates. Record the approximate diagnosis date, which can bear on filing deadlines.
6. Act promptly. Because statutes of limitation can bar late claims, do not delay in seeking a professional evaluation.
7. Consult a qualified attorney. Have a licensed lawyer review the specific facts and the law that applies in your state.

For general background while you research, CredibleLaw maintains educational resources on mass torts and emerging mass torts, as well as overviews of personal injury and wrongful death claims.

Conclusion

The Roundup litigation captures how science, regulation, and law can pull in different directions. Regulators in the United States and much of the world consider glyphosate unlikely to cause cancer as used, while the WHO’s cancer agency classified it as a probable carcinogen — and juries, presented with both narratives, have reached differing verdicts. The result is one of the largest and most closely watched mass torts in American history, now shaped by a proposed multibillion-dollar settlement and a pending U.S. Supreme Court decision on federal preemption.

For anyone personally affected, two themes stand out. Documentation matters — medical records, exposure history, and timing are the building blocks of any evaluation. And timing matters — statutes of limitation can foreclose claims that are never filed in time. Because every situation turns on its own facts and on a fast-moving legal landscape, the most reliable next step is a conversation with a qualified attorney who can assess the specifics and explain the current state of the law.

Educational disclaimer. This article is provided for general informational purposes only and does not constitute legal or medical advice. It does not create an attorney-client relationship and makes no guarantee regarding eligibility, compensation, or outcome. The Roundup litigation is evolving; confirm current developments and your legal options with a licensed attorney in your jurisdiction. CredibleLaw operates as a legal referral resource connecting individuals with attorneys.

Authoritative Sources

This guide draws on primary and authoritative sources, including:

• U.S. Environmental Protection Agency (EPA) — glyphosate
• International Agency for Research on Cancer (IARC), World Health Organization
• U.S. Judicial Panel on Multidistrict Litigation (JPML)
• National Cancer Institute (NCI)
• Bayer — official Roundup litigation updates
• Peer-reviewed scientific and medical literature (e.g., reviews published in journals such as Environmental Sciences Europe and Environmental Health) on glyphosate carcinogenicity and the EPA–IARC divergence.