MON863, like MON810, is a genetically modified Bt corn type developed by US seed corporate group Monsanto – here, too, genes from the soil bacterium Bacillus thuringiensis (Bt) are inserted into the corn's genetic material. Due to this genetic alteration, MON863 is resistant to certain pests compared to conventional corn. 

After a 90-day rat feeding trial carried out in 2000 (but first published in 2006) by Monsanto, the GM corn was rated as safe and hence licensed by the European Food Safety Authority (EFSA) in 2004. EU approval was granted in 2005 for use in feed and in 2006 for use in food. Unlike MON810, MON863 is not approved for cultivation in the EU.

The results of the 90-day feeding trial were statistically re-evaluated in 2007 by scientists of the French organization Comité de Recherche et d'Information Indépendantes sur le génie Génétique (CRIIGEN). They found out that the statistical methods used by Monsanto in the first evaluation were not accurate enough to be able to discover health harming effects. In their new analysis of the findings, the scientists detected harmful effects of MON863 for the liver and kidney. Compared to animals which were fed conventional corn, differences in the composition of blood and urine could be found in animals which were fed with GM corn (amongst others, differences in blood fat level, blood sugar level, as well as phosphorous and sodium content in urine were detected). Moreover, the re-evaluation of the feeding trial showed abnormal changes in the rats’ growth and weight.

Occasioned by the publication of the CRIIGEN-study, EFSA conducted a comparative survey of both studies regarding the statistical methods employed respectively. They came to the conclusion that the divergences in the results of both studies were only caused by a different interpretation of the data laying the basis of the studies. The survey of the data itself had been conducted correctly by Monsanto. The critical findings of the CRIIGEN-study could be ascribed to the application of imprecise statistical methods. In a precise statistical survey, the results were inconspicuous regarding all parameters examined, in particular growth and weight. Therefore, EFSA did not see a reason for annihilating the authorisation of MON863.