A new study reveals diquat, the herbicide used in some weedkiller products including Roundup, can cause significant harm to gut bacteria and damage organs in multiple ways. Diquat is widely employed in US vineyards and orchards, but its toxicity has raised concerns globally.
Research suggests diquat is more toxic than glyphosate, a controversial herbicide substance previously used in Roundup. Despite this, the EPA has resisted calls for a ban, allowing diquat-based Roundup products to hit shelves last year. The Centers for Biological Diversity warns that diquat’s “nasty” effects on human health make its use regrettable.
Diquat is also considered a neurotoxin, carcinogen, and linked to Parkinson’s disease. An analysis by Friends of the Earth found diquat 200 times more toxic than glyphosate in terms of chronic exposure. Bayer, which manufactures Roundup, has faced nearly 175,000 lawsuits alleging product harm.
Studies show diquat damages organs and gut bacteria by weakening the gut lining, allowing toxins to enter the bloodstream, and triggering inflammation. Damage to the lining also inhibits nutrient absorption and energy metabolism. The substance harms kidneys, lungs, and liver, causing irreversible damage and inflammation.
Despite the risks, the EPA has not reviewed diquat’s safety, and regulatory advocates are preoccupied with battles over other toxic substances like glyphosate and chlorpyrifos. Donley notes that US pesticide regulations are too weak to ban ingredients, even if will exists, citing a court-ordered overturn of the 2022 chlorpyrifos ban. The EPA’s approach is characterized as being overly focused on industry interests, with a “necessary evil” philosophy prioritizing toxic pesticides over public health concerns.
Source: https://www.theguardian.com/environment/2025/jul/06/weedkiller-diquat-organ-damage-study