Study that said glyphosate herbicide is safe retracted 25 years after publication

OTTAWA — Environmental groups say Health Canada needs to take action after an influential research article on the safety of a popular weed-killer was retracted by its publisher.

A paper published in 2000 in the journal Regulatory Toxicology and Pharmacology concluded that the herbicide glyphosate, the main ingredient in Roundup, is safe for humans.

The study has been cited more than 700 times in scientific publications, including Health Canada’s 2017 re-evaluation of glyphosate use, which found the chemical was “unlikely to pose a human cancer risk.”

But the original article was retracted last week and the publisher says its conclusions were based only on unpublished studies from Monsanto, the company that makes Roundup.

The publisher also says there is evidence from a lawsuit in the U.S. that suggests Monsanto employees helped write the article, without acknowledgment, and the authors may have been paid by the company.

Beatrice Olivastri, CEO of Friends of the Earth Canada, is calling on Health Canada to put a moratorium on glyphosate sales and says the health minister should order an expedited special review of the pesticide.

This report by The Canadian Press was first published Dec. 4, 2025.