The remarkable efficiency with which electrolyte homeostasis is restored following a disturbance in electrolyte hemodynamics has been the subject of many important papers (1–6). Much less is known, however, about the ability of the aged person to maintain this homeostasis. Because sodium is the cornerstone of electrolyte balance and imbalance, we decided to investigate the manner in which elderly people cope with both scarcity and abundance of electrolytes in their diets. The roles of calcium and potassium in maintaining electrolyte balance are less well delineated than that of sodium, so calcium and potassium determinations were also included in this study.