Is the Roundup Herbicide Diquat Toxic?

According to a new review of more than 100 studies suggests diquat, an herbicide now used in Roundup products, could cause direct damage the intestines and could trigger a toxic chain reaction in the rest of the body—possibly putting the liver, kidney, and lungs at risk.

Is the New Roundup Formula Even More Toxic?

Diquat, which has replaced glyphosate in Bayer’s Roundup herbicides, is banned in the European Union. And maybe for good reason. The herbicide has been studied for years and has global restrictions due to potential toxic effects on the liver and kidneys. A published study in May 2025 in Frontiers in Pharmacology, now adds fuel to the fire, suggesting the chemical may harm the intestines as well. If you were wondering, yes, diquat is widely used in the United States, and in much of Latin America.

Studies conclude that diquat may weaken the intestinal barrier, kill off beneficial bacteria, interfere with nutrient absorption, and trigger chronic inflammation. This is particularly important because of how important gut health is to human health. Poor gut health can have serious repercussions throughout the body. Studies suggest that diquat’s harmful impact on the intestine can extend to other organs like the kidneys, lungs and liver. Many experts suggested there were risks before, and this adds to the case against the new Roundup formula safety profile.

In their report, the researchers wrote, “Studies show that Diquat primarily enters the body through the digestive tract, leading to poisoning. The core mechanism of its toxicity involves reactive oxygen species (ROS)-induced oxidative stress, which not only directly damages the intestinal barrier function but also exacerbates inflammation and systemic toxicity by disrupting the balance of the gut microbiota and the normal production of metabolic products.”

Diquat is banned in the EU and the U.K. due to both environmental and potential human health risks. Popular herbicides like diquat, and its toxic cousin paraquat (also banned in the EU), can remain active in water and soil for up to 10 days, likely entering water sources and the food chain.

Diquat was ultimately banned because of the risks it poses to residents and passersby near the fields where it was sprayed, not mention those who actually work closely with the herbicides in the fields. Even if a farmworker is wearing personal protective equipment (PPE), European Food Safety Agency concluded in a report that worker exposure would exceed the maximum acceptable level by more than 4,000 percent.

Joe Lyon and his team of toxic exposure lawyers are investigating cancers and other serious illnesses linked to occupational toxic exposure. We have filed numerous occupational cancer cases and settled many Roundup cancer claims on behalf of plaintiffs nationwide. Contact our attorneys for a free consultation and to seek compensation for the loss of health, loss of life, and financial damages.