A long-term study claiming to show toxic effects on rats of the herbicide Roundup and genetically modified (GM) Roundup-tolerant maize (corn) was originally published in 2012 (Seralini et al. 2012). It roused significant controversy. The journal retracted the article — although it had been peer-reviewed and elicited no “red flags” during the review process. The authors stood by their findings. In 2014, this study was re-published in a different journal (Seralini et al. 2014).
While some of the results of this study are striking, especially the report of toxic effects of small amounts of the herbicide Roundup (glyphosate) in the rats’ drinking water, we also believe that the interpretation of the findings is difficult especially because of the small number of rats used in the study (10 rats per test group). (Other studies on feeding toxicity share some of this study’s shortcomings; see Meyer and Hilbeck 2013; and http://natureinstitute.org/nontarget/reports/gm_safety_001.php.) Nonetheless we feel that in the interest of open communication, and because the study was carried out by qualified scientists and was peer-reviewed, we should include it among the studies on the unintended effects of genetic manipulation.