The scientific journal Regulatory Toxicology and Pharmacology has issued a rare retraction of a highly cited study on the safety of the pesticide glyphosate, the main ingredient in the popular weedkiller Roundup.

Glyphosate is one of the most used herbicides in the world. Monsanto patented it and it became best known as the active ingredient in Roundup-branded herbicide. It is now found in hundreds of products. Some food safety advocates say it is left on foods as a residue that can cause health problems.