Diquat, a widely used herbicide and replacement for glyphosate in products like Roundup, has been shown to cause serious and systemic harm throughout the body.
Diquat is a herbicide first introduced in the 1950s, originally used to speed up the drying of crops before harvest and to eliminate aquatic weeds. Though known to be toxic, it was used widely for decades because it effectively desiccated plants, making mechanical harvesting easier and more efficient. Diquat is being used as a replacement largely because of the growing restrictions and public backlash against glyphosate. As glyphosate, the world’s most widely used herbicide, has been linked to cancer and other health issues, many countries and companies are phasing it out or tightening regulations around its use. This has created a demand for alternative herbicides.
Diquat is chemically different but serves a similar function: drying out crops before harvest and killing weeds. Because it wasn’t as publicly scrutinized as glyphosate, manufacturers and farmers began turning to it as a substitute. However, this shift happened without fully addressing its own toxic profile.
According to a 2025 review published in Frontiers in Pharmacology:
- Diquat enters the digestive tract and generates high levels of reactive oxygen species (ROS), damaging the gut lining and disrupting tight-junction proteins.
- This leads to increased intestinal permeability, or “leaky gut,” which allows bacterial endotoxins and other harmful compounds to enter the bloodstream and trigger widespread inflammation.
- Diquat also disrupts the gut microbiome and promotes the release of inflammatory cytokines such as TNF-α, IL-6, and IL-1β. Once in the bloodstream, the damage spreads systemically.
- In the kidneys, diquat targets renal tubular cells, leading to oxidative stress and acute kidney injury. In the liver, it disrupts mitochondrial respiration and reduces ATP production, impairing the organ’s ability to detoxify and regulate metabolism. It also causes lung tissue damage through oxidative stress and has been linked to neurological toxicity.
Despite mounting evidence that diquat causes widespread organ damage, U.S. regulators have not initiated a formal review or restriction of its use. It has been banned in the EU, UK, Switzerland, and China after regulators highlighted high risks to bystanders, workers, and wildlife, but it remains in active circulation within the U.S. including in newly formulated glyphosate products like Roundup.
Right now there is no widespread U.S. movement to ban diquat. Most legislative energy remains focused on chemicals like glyphosate, paraquat, and chlorpyrifos. Diquat remains overshadowed, even though it is now classified by some experts as 200× more toxic than glyphosate in chronic exposure models.
Companies often respond to public pressure by removing a controversial chemical, not necessarily to make products safer, but to appear responsible. That’s exactly what happened with BPA (bisphenol A), a xenoestrogen widely used in plastics, food containers, and baby bottles. When concerns about its hormone-disrupting effects became mainstream, manufacturers began labeling their products “BPA-free.” But instead of removing the hazard entirely, they replaced BPA with nearly identical compounds like BPS and BPF, chemicals that turned out to be just as harmful.
This pattern is called regrettable substitution: the practice of swapping one dangerous chemical for another closely related one that hasn’t yet been regulated or studied as thoroughly. As glyphosate (Roundup) faces increased scrutiny and restrictions, diquat is quietly being used more often in its place. While it may be less well known, research shows diquat may be even more toxic, capable of damaging the liver, lungs, brain, and kidneys.
This is a reflection of a regulatory system that reacts to public pressure by banning individual substances without addressing the broader pattern of chemical harm. Until policies shift to evaluate chemical families and long-term effects, we’ll continue to see these substitutions. But awareness is the first step. The more we understand how these patterns work, the better equipped we are to make informed choices, support better regulation, and push for systems that prioritize our health.
The best thing we can do to avoid the health impacts of pesticides is to mitigate exposure wherever possible and push for systemic change. While we may not have complete control over environmental contamination, we can take steps to reduce personal risk and advocate for policies that protect public health.
- Buy organic when possible.
- Visit farmer’s markets and build relationships with local farmers.
- Grow your own food.
- Soak all produce in baking soda or vinegar.
- Filter your drinking and bath water.
- Avoid lawns and landscaping sprayed with herbicides.
- Call your senators: legislative action is necessary to reduce pesticide exposure on a larger scale.