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.