Naturally occurring antinutrients and food toxicants, and those formed during food processing, adversely affect the nutri tional quality and safety of foods. Because of the need to improve food quality and safety by plant breeding, fortification with appropriate nutrients, and processing methods, and because of the growing concern about possible direct relationships between diet and diseases, research is needed to: (1) evaluate the nutritive quality and safety of crops and fortified, supplemented, and processed foods; (2) define conditions that favor or minimize the formation of nutritionally antagonistic and toxic compounds in foods; and (3) define the toxicology, metabolism, and mechanisms of the action of food ingredients and their metabolites. As scientists interested in improving the safety of the food supply, we are challenged to respond to the general need for exploring: (1) possible adverse consequences of antinutrients and food toxicants; and (2) factors which contribute to the formation and inactivation of undesirable compounds in foods. Medical research offers an excellent analogy. Studies on causes and mechanisms of disease processes are nearly always accompanied by parallel studies on preventive measures and cures. Such an approach offers the greatest possible benefits to the public.