ROUNDUP GUIDE
What Is Glyphosate?
Last updated: June 9, 2026
Glyphosate is a widely used herbicide — the chemical that kills weeds in Roundup and many other weed-killer products. It has been applied for decades across agriculture, landscaping, and home lawn care. It is also at the center of years of litigation over whether long-term exposure is associated with certain cancers. This page explains what glyphosate is in plain English, what it is used for, and why people researching it often end up reading about lawsuits.
This page provides general educational information only and does not constitute medical or legal advice. Discuss any health concerns with a qualified medical professional.
- Glyphosate is the active ingredient in Roundup and many other herbicides.
- It kills weeds by blocking an enzyme pathway (the shikimate pathway) that plants need but humans and animals do not have.
- It is used in farming, commercial landscaping, grounds maintenance, and residential lawn care.
- It is the subject of major litigation over alleged links to non-Hodgkin lymphoma.
Glyphosate, Defined
Glyphosate is a broad-spectrum systemic herbicide. "Broad-spectrum" means it kills a wide range of plants rather than targeting one species. "Systemic" means the plant absorbs it and moves it internally, down to the roots, rather than the chemical only affecting the surface it touches. It was first brought to market in the 1970s and went on to become one of the most heavily used agricultural chemicals in the world.
How Glyphosate Works
Glyphosate blocks an enzyme called EPSP synthase, part of what is known as the shikimate pathway. Plants and some microorganisms rely on this pathway to make certain proteins they need to grow. Humans and animals do not have this pathway, which is part of why glyphosate was historically marketed as having a favorable safety profile compared with older herbicides. Whether long-term exposure carries health risks for people is a separate and contested question, and it is the issue at the heart of the litigation.
Glyphosate vs. Roundup
People often use the two words interchangeably, but they are not the same thing. Glyphosate is the active chemical ingredient. Roundup is a brand name for a family of herbicide products, originally developed by Monsanto and later owned by Bayer, that contain glyphosate along with other ingredients such as surfactants that help the product spread and stick to plants. Many non-Roundup products on store shelves also contain glyphosate.
What Glyphosate Is Used For
- Agricultural weed control on farms and fields
- Use on genetically modified, glyphosate-tolerant crops
- Commercial landscaping and grounds maintenance
- Residential lawn, garden, and driveway weed control
- Vegetation management along roads, rail lines, and utility corridors
Why People Researching Glyphosate Often Read About Lawsuits
In 2015, the International Agency for Research on Cancer (IARC), part of the World Health Organization, classified glyphosate as "probably carcinogenic to humans." Other regulators, including the U.S. Environmental Protection Agency, have reached different conclusions. That scientific disagreement, combined with decades of widespread use, is why glyphosate became the subject of large-scale litigation. To understand the legal side, see Roundup Cancer Lawsuits and the regulatory analysis in Glyphosate Lawsuits: EPA, Bayer and the Supreme Court.
Common Questions
Is glyphosate dangerous to humans?
Scientific and regulatory bodies have disagreed on this question. Some, including IARC, have classified it as probably carcinogenic; others have not. For a fuller discussion, see Is Roundup Dangerous?
What are the symptoms of glyphosate exposure?
People research a range of reported effects. See Glyphosate Exposure Symptoms for a plain-English overview.
