Recent advances in nutrition have focused on the pharmacologic actions of individual amino
acids and their organ-specific reactions. Thus, phenylalanine stimulates brain and intestinal
cholecystokinins, dietary tyrosine is a precursor of catocholamines, and tryptophan is both a
stimulus for and a precursor of serotonin synthesis. Within this context, much work has been
done regarding the role of arginine as a therapeutic agent; this review summarizes the new
body of work, presents a personal critique, and offers perspectives for future re-search.