The notion that vitamins, minerals, and other "supplemental" nutrients profoundly change behavior, mood, and intellect has origins as old as recorded history. Research has indeed suggested connections between nutrient deficiencies and behavior problems, but correlations are not the same as causality. This "Abell Report" is an attempt to get past the "he said/she said" debate, and to review, analyze, and come to some conclusions about the evidence for and against providing mass supplementation in the schools as a means of influencing behavior and cognition. It looks for common ground between the skeptics and the advocates, and offers some next steps if school officials find sufficient evidence to warrant a look at designing a supplementation pilot program or study in Baltimore City schools. Although suggestive studies continue to pile up, ongoing scientific uncertainty remains a major obstacle to public-health initiatives to feed supplements to at-risk populations--too little is understood about the role each nutrient might be playing in these studies. The recommendation to conduct more studies--or just better ones--is likely to frustrate those who want faster action, but the credible experts in the field see no real alternative. Supplements are no "magic bullet" to stop violence, antisocial behavior, depression, or any other behavior in schools or anywhere else.