Weedkiller ingredient banned in the UK, EU, China, but widely used in US can damage organs and gut bacteria (May 2025, review) Effect of Diquat on gut health: molecular mechanisms, toxic effects, and protective strategies Review

[Michael Harrop]

https://www.theguardian.com/environment/2025/jul/06/weedkiller-diquat-organ-damage-study
https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2025.1562182/full

The herbicide ingredient used to replace glyphosate in Roundup and other weedkiller products can kill gut bacteria and damage organs in multiple ways, new research shows.

The ingredient, diquat, is widely employed in the US as a weedkiller in vineyards and orchards, and is increasingly sprayed elsewhere as the use of controversial herbicide substances such as glyphosate and paraquat drops in the US.

But the new piece of data suggests diquat is more toxic than glyphosate, and the substance is banned over its risks in the UK, EU, China and many other countries. Still, the EPA has resisted calls for a ban, and Roundup formulas with the ingredient hit the shelves last year.

the new piece of data suggests diquat is more toxic than glyphosate

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Diquat is a widely used bipyridyl herbicide that is extensively applied in agricultural production and water management due to its high efficacy in weed control. However, its environmental persistence and the toxic effects it induces have raised widespread concern. 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. This review systematically summarizes the physicochemical properties of Diquat, with a focus on analyzing the mechanisms by which it damages the gut tissue structure, barrier function, and microbiota after digestive tract exposure. The aim is to provide theoretical support for a deeper understanding of Diquat’s toxic mechanisms and its digestive tract-centered toxic characteristics, laying a scientific foundation for the development of effective interventions and protective strategies against its toxicity.

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