According to the American Department of Agriculture, organophosphoric pesticides are suspected of inducing neurological side-effects in humans and are present in many alimentary products. Children were submitted to three successive diets : conventional, organic, conventional. The organic phase was accompanied by a reduced concentration of metabolites, malathion, and chloropyrifos in their urines. Returning to a conventinal diet increased these concentrations. This shows that the principle source of exposure of children to these pollutant is their food.