The second perspective, involving elimination of unwelcome chemicals that may have adverse effects, includes the research on both environmental toxins (7) and food "additives" (usually meaning colors, flavors, and preservatives). This is the topic addressed by Stevenson et al.'s group in this issue of the Journal (8), and their data move this field forward significantly by providing important information on potential mechanisms. As with the research on supplementation, the elimination perspective has also been explored extensively over a long period of time, at least since Feingold's observations in the 1970s. The empirical data have demonstrated a relationship between food additives and behavior in some children with some additives, but not consistently (9). One interesting effect of the uneven scientific results has been a dramatic split between parent advocacy groups, powered by individuals convinced of the meaningful role of additive-free food for their children, and the scientific community, which has been stumped as to how to tease out the importance and relevance of additive-behavior interactions. Uneven results in science are often the result of weakly powered studies and poor methodology, but that does not appear to be the case for this topic. Some good data have been generated over the years from randomized controlled trials and other study designs. What appeared to be missing up until now was a way to understand individual differences in response to exposure.